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Document and Entity Information - shares	6 Months Ended
Jun. 30, 2014	Jul. 21, 2014
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2014
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	Q2
Trading Symbol	TNDM
Entity Registrant Name	TANDEM DIABETES CARE INC
Entity Central Index Key	0001438133
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		23,463,233

Condensed Balance Sheets - USD ($)	Jun. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 64,207,844	$ 124,385,137
Restricted cash	2,000,000	2,050,000
Short-term investments	30,097,363	5,095,331
Accounts receivable, net	4,362,238	5,298,502
Inventory	11,121,021	10,330,156
Prepaid and other current assets	2,634,098	1,830,056
Total current assets	114,422,564	148,989,182
Property and equipment, net	12,476,109	9,885,985
Patents, net	2,538,560	2,697,220
Other long term assets	579,823	642,746
Total assets	130,017,056	162,215,133
Current liabilities:
Accounts payable	2,520,912	2,352,037
Accrued expense	1,686,425	1,873,565
Employee-related liabilities	5,497,815	5,876,011
Deferred revenue	514,309	411,423
Other current liabilities	2,991,219	4,086,196
Total current liabilities	13,210,680	14,599,232
Notes payable-long-term	29,392,352	29,396,571
Deferred rent-long-term	3,004,629	1,886,508
Other long-term liabilities	861,928	795,640
Total liabilities	46,469,589	46,677,951
Commitments and contingencies
Stockholders' equity:
Common stock, $0.001 par value; 100,000,000 shares authorized, 23,455,483 and 22,925,614 shares issued and outstanding at June 30, 2014 (unaudited) and December 31, 2013, respectively	23,455	22,926
Additional paid-in capital	293,861,259	284,705,251
Accumulated other comprehensive income	12,282
Accumulated deficit	(210,349,529)	(169,190,995)
Total stockholders' equity	83,547,467	115,537,182
Total liabilities and stockholders' equity	$ 130,017,056	$ 162,215,133

Condensed Statements of Operations and Comprehensive Loss (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Income Statement [Abstract]
Sales	$ 10,254,640	$ 5,527,744	$ 18,320,108	$ 10,986,151
Cost of sales	6,805,890	5,121,866	14,004,700	8,539,866
Gross profit	3,448,750	405,878	4,315,408	2,446,285
Operating expenses:
Selling, general and administrative	18,068,303	11,324,309	36,109,208	18,208,386
Research and development	3,698,245	2,758,761	7,361,564	5,081,238
Total operating expenses	21,766,548	14,083,070	43,470,772	23,289,624
Operating loss	(18,317,798)	(13,677,192)	(39,155,364)	(20,843,339)
Other income (expense), net
Interest and other income	30,784	234	49,284	460
Interest and other expense	(909,577)	(1,170,696)	(2,052,454)	(2,337,871)
Change in fair value of stock warrants		(453,224)		(3,283,604)
Total other expense, net	(878,793)	(1,623,686)	(2,003,170)	(5,621,015)
Net loss	(19,196,591)	(15,300,878)	(41,158,534)	(26,464,354)
Other comprehensive gain or loss:
Unrealized gain (loss) on short-term investments	(1,551)		12,282
Comprehensive loss	$ (19,198,142)	$ (15,300,878)	$ (41,146,252)	$ (26,464,354)
Net loss per share, basic and diluted	$ (0.83)	$ (72.50)	$ (1.79)	$ (75.42)
Weighted average shares used to compute basic and diluted net loss per share	23,097,760	211,035	23,017,424	350,883

Condensed Statements of Cash Flows (Unaudited) - USD ($)	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Operating activities
Net loss	$ (41,158,534)	$ (26,464,354)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	1,918,188	1,706,386
Provision for allowance for doubtful accounts	100,966	95,924
Provision for inventory reserve	163,246	102,946
Interest expense related to amortization of debt discount and debt issuance costs	133,704	297,028
Change in fair value of common and preferred stock warrants		3,283,604
Amortization of discount on short-term investments	(20,883)
Stock-based compensation expense	7,302,263	644,452
Loss on disposal of property and equipment		18,691
Changes in operating assets and liabilities:
Restricted cash		(178,981)
Accounts receivable	835,298	(416,941)
Inventory	(1,007,756)	(3,630,987)
Prepaid and other current assets	(804,042)	108,333
Accounts payable	76,775	(155,895)
Accrued expense	(187,139)	49,824
Employee-related liabilities	(378,196)	1,950,059
Deferred revenue	102,886	(1,779,709)
Other current liabilities	(1,242,490)	339,132
Deferred rent	1,438,833	(288,580)
Other long term liabilities	66,288	343,344
Net cash used in operating activities	(32,660,593)	(23,975,724)
Investing activities
Purchase of short-term investments	(35,828,867)
Purchase of property and equipment	(4,290,457)	(1,416,078)
Purchase of patents	(173,200)	(500,000)
Proceeds from sales and maturities of short-term investments	10,860,000
Net cash used in investing activities	(29,432,524)	(1,916,078)
Financing activities
Issuance of notes payable, net of issuance costs	29,925,000	29,249,054
Restricted cash in connection with notes payable and corporate credit card	50,000	(2,000,000)
Principal payments on notes payable	(30,000,000)	(4,396,323)
Issuance of preferred stock for cash, net of offering costs		15,999,532
Proceeds from issuance of common stock	1,940,824	9,461
Net cash provided by financing activities	1,915,824	38,861,724
Net (decrease) increase in cash and cash equivalents	(60,177,293)	12,969,922
Cash and cash equivalents at beginning of period	124,385,137	17,162,730
Cash and cash equivalents at end of period	64,207,844	30,132,652
Supplemental disclosures of cash flow information
Interest paid	1,918,750	2,561,667
Supplemental schedule of noncash investing and financing activities
Unrealized gain on short-term investments	12,282
Property and equipment included in accounts payable	$ 59,196	241,761
Common and preferred stock warrants issued, including incremental value of modification of warrants		$ 437,268

Organization and Basis of Presentation	6 Months Ended
Organization and Basis of Presentation	Jun. 30, 2014
Accounting Policies [Abstract]
Organization and Basis of Presentation	1. Organization and Basis of Presentation *The Company* Tandem Diabetes Care, Inc. is a medical device company focused on the design, development and commercialization of products for people with insulin-dependent diabetes. Unless the context requires otherwise, the terms the “Company” or “Tandem” refer to Tandem Diabetes Care, Inc. The Company designed and commercialized its flagship product, the t:slim Insulin Delivery System, or t:slim, based on its proprietary technology platform and unique consumer-focused approach. The U.S. Food and Drug Administration (“FDA”) cleared t:slim in November 2011 and the Company commenced commercial sales of t:slim in the United States in the third quarter of 2012. Tandem was originally incorporated in the state of Colorado on January 27, 2006 under the name Phluid Inc. On January 7, 2008, the Company was reincorporated in the state of Delaware for the purposes of changing its legal name from Phluid Inc. to Tandem Diabetes Care, Inc. and changing its state of incorporation from Colorado to Delaware. *Basis of Presentation* The Company has prepared the accompanying unaudited condensed financial statements in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and disclosures required by U.S. GAAP for complete financial statements. In the opinion of management, all adjustments which are of a normal and recurring nature, considered necessary for a fair presentation have been included. Interim financial results are not necessarily indicative of results anticipated for the full year. These unaudited condensed financial statements should be read in conjunction with the Company’s audited financial statements and footnotes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013, from which the balance sheet information herein was derived. *Initial Public Offering* In November 2013, the Company completed its initial public offering of 8,000,000 shares of its common stock at a public offering price of $15.00 per share. Net cash proceeds from the initial public offering were approximately $108.3 million, after deducting underwriting discounts, commissions and estimated offering related transaction costs payable by the Company. In November 2013, the underwriters also exercised their overallotment option and purchased an additional 1,200,000 shares of the Company’s common stock, from which the Company received cash proceeds, net of underwriting discounts and commissions, of approximately $16.7 million. In connection with the closing of the initial public offering, all of the Company’s shares of convertible preferred stock outstanding at the time of the offering were automatically converted into 13,403,747 shares of common stock. In addition, all outstanding preferred stock warrants were automatically converted into warrants to purchase an aggregate of 1,171,352 shares of common stock. *Reverse Stock Splits* In October 2013, the Board of Directors approved a 1-for-1.6756 reverse stock split of the Company’s common stock. All share and per share information included in the accompanying unaudited condensed financial statements and notes to the unaudited condensed financial statements give retroactive effect to this reverse stock split of the common stock. *Voluntary Recall* On January 10, 2014, the Company announced a voluntary recall of select lots of cartridges used with the t:slim that may be at risk of leaking. The cause of the recall was identified during the Company’s internal product testing. The recall was expanded on January 20, 2014 to include additional lots of affected cartridges used with the t:slim. The Company incurred approximately $1.7 million in direct costs associated with the recall. The Company recorded a cost of sales charge of approximately $1.3 million in the fourth quarter of 2013 and recorded a cost of sales charge for the remainder in the first quarter of 2014 for affected cartridges shipped in 2014. The Company does not currently expect any further direct financial impact of the recall beyond these costs. The total cost of the recall consisted of approximately $0.7 million associated with the return and replacement of affected cartridges in the field and approximately $1.0 million for the write-off of affected cartridges within the Company’s internal inventory.

- Definition

The entire disclosure for organization, consolidation and basis of presentation of financial statements disclosure.

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+ Details

Summary of Significant Accounting Policies

6 Months Ended

Jun. 30, 2014

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Use of Estimates

The preparation of the financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and the disclosure of contingent assets and liabilities in the Company’s financial statements and accompanying notes as of the date of the financial statements. Actual results could differ from those estimates and assumptions.

Restricted Cash

Restricted cash as of June 30, 2014 represents a $2.0 million minimum cash balance requirement in connection with the Capital Royalty Term Loan (see Note 6 “Loan Agreements”).

Accounts Receivable

The Company grants credit to various customers in the normal course of business. The Company maintains an allowance for doubtful accounts for potential credit losses. Provisions are made, generally, for receivables greater than 120 days past due and based upon a specific review of other outstanding invoices. Uncollectible accounts are written off against the allowance after appropriate collection efforts have been exhausted and when it is deemed that a balance is uncollectible.

Concentration of Credit Risk

Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash, cash equivalents, short-term investments and accounts receivable. The Company maintains deposit accounts in federally insured financial institutions in excess of federally insured limits. The Company also maintains investments in money market funds that are not federally insured. Additionally, the Company has established guidelines regarding investment instruments and their maturities, which are designed to maintain preservation of principal and liquidity.

The following table summarizes customers who accounted for 10% or more of net accounts receivable:


	June 30, 2014			December 31, 2013
CCS Medical, Inc.		16.8	%		21.4	%
Edgepark Medical Supplies, Inc.		18.9	%		13.1	%

The following table summarizes customers who accounted for 10% or more of sales for the periods presented:


	Three Months Ended June 30,						Six Months Ended June 30,
	2014			2013			2014			2013
CCS Medical, Inc.		14.6	%		N/A			15.7	%		N/A
Edgepark Medical Supplies, Inc.		16.5	%		14.9	%		16.0	%		17.2	%

Fair Value of Financial Instruments

The carrying amounts of cash and cash equivalents, accounts receivable, accounts payable, accrued expense, and employee-related liabilities are reasonable estimates of their fair value because of the short maturity of these items. Short-term investments are carried at fair value. Based on the borrowing rates currently available for loans with similar terms, the Company believes that the fair value of its long-term debt approximates its carrying value.

Revenue Recognition

Revenue is generated in the United States from the sale of the t:slim Pump, disposable cartridges and infusion sets to individual customers and third-party distributors that resell the product to insulin-dependent diabetes customers. The Company is paid directly by customers who use the products, distributors and third-party insurance payors.

Revenue is recognized when persuasive evidence of an arrangement exists, delivery has occurred and title passed, the price is fixed or determinable, and collectability is reasonably assured. These criteria are applied as follows:

•

The evidence of an arrangement generally consists of contractual arrangements with distributors or direct customers.

•

Transfer of title and risk and rewards of ownership are passed upon shipment of the pump to distributors or upon delivery to the customer.

•

The selling prices are fixed and agreed upon based on the contracts with distributors, the customer and contracted insurance payors, if applicable. For sales to customers associated with insurance providers with whom there is no contract, revenue is recognized upon collection of cash at which time the price is determinable. The Company generally does not offer rebates to its distributors and customers.

•

The Company considers the overall creditworthiness and payment history of the distributor, customer and the contracted insurance payor in concluding whether collectability is reasonably assured.

Prior to the first quarter of 2013, t:slim Pump sales were recorded as deferred revenue until the Company’s 30-day right of return expired because it did not have sufficient history to be able to reasonably estimate returns. At December 31, 2012, $1.9 million was recorded as deferred revenue. Beginning in the first quarter of 2013, the Company began recognizing t:slim Pump revenue when all the revenue recognition criteria above are met, as it established sufficient history in order to reasonably estimate product returns. As a result of this change, a one-time adjustment was recorded during the six month period ended June 30, 2013, to recognize previously deferred revenue and cost of sales of $1.9 million and $1.1 million, respectively.

Revenue Recognition for Arrangements with Multiple Deliverables

The Company considers the deliverables in its product offering as separate units of accounting and recognizes deliverables as revenue upon delivery only if (i) the deliverable has standalone value and (ii) if the arrangement includes a general right of return relative to the delivered item(s), delivery or performance of the undelivered item(s) is probable and substantially controlled by us. The Company allocates consideration to the separate units of accounting, unless the undelivered elements were deemed perfunctory and inconsequential. The Company uses the relative selling price method, in which allocation of consideration is based on vendor-specific objective evidence (“VSOE”) if available, third-party evidence (“TPE”), or if VSOE and TPE are not available, management’s best estimate of a standalone selling price (“ESP”) for the undelivered elements.

In February 2013, the FDA cleared t:connect, the Company’s cloud-based data management application, which is made available upon purchase by t:slim Pump customers. This service is deemed an undelivered element at the time of the t:slim sale. Because the Company has neither VSOE nor TPE for this deliverable, the allocation of revenue is based on the Company’s ESP. The Company establishes its ESP based on estimated cost to provide such services, including consideration for a reasonable profit margin and corroborated by comparable market data. The Company allocates fair value based on management’s ESP to this element at the time of sale and recognizes the revenue over the four year hosting period. Deferred revenue for the t:connect hosting services was $0.4 million and $0.2 million at June 30, 2014 and December 31, 2013, respectively. All other undelivered elements at the time of sale are deemed inconsequential or perfunctory.

Product Returns

The Company offers a 30-day right of return for its t:slim Pump customers from the date of shipment, provided a physician’s confirmation of the medical reason for the return is received. Estimated allowances for sales returns are based on historical returned quantities as compared to t:slim Pump shipments in the same period. The return rate is then applied to the sales of the period to establish a reserve at the end of the period. The return rates used in the reserve are adjusted for known or expected changes in the marketplace when appropriate. The allowance for product returns at June 30, 2014 and December 31, 2013 was $0.2 million. Actual product returns have not differed materially from estimated amounts reserved.

Warranty Reserve

The Company generally provides a four-year warranty on its t:slim Pump to end user customers and may replace any pumps that do not function in accordance with the product specifications. Any pump returned to the Company may be refurbished and redeployed. Additionally, the Company offers a six month warranty on t:slim cartridges and infusion sets. Estimated warranty costs are recorded at the time of shipment. Warranty costs are estimated based on the current product cost considering a mix of new and refurbished pump costs, actual experience and expected failure rates from test studies performed in conjunction with the clearance of the Company’s product with the FDA to support the longevity and reliability of its t:slim Pump. The Company evaluates the reserve quarterly and makes adjustments when appropriate. At June 30, 2014 and December 31, 2013, the warranty reserve was $0.9 million and $1.1 million, respectively. Of the total $0.9 million warranty reserve at June 30, 2014, $0.3 million was recorded as a component of other current liabilities and $0.6 million was recorded in other long-term liabilities. In addition, of the $1.1 million warranty reserve at December 31, 2013, $0.3 million was related to potential replacements associated with the voluntary product recall of selected lots of cartridges. The Company does not expect further replacements beyond June 30, 2014. As such, there was no warranty reserve at June 30, 2014 for such potential replacements. Actual warranty costs have not differed materially from estimated amounts reserved.

The following table provides a reconciliation of the change in product warranty liabilities through June 30, 2014 (in thousands):


Balance at December 31, 2013	$	1,123
Provision for warranties issued during the period		1,396
Settlements made during the period		(1,617	)

Balance at June 30, 2014	$	902

Stock-Based Compensation

The Company estimates the fair value of stock options and shares issued to employees under the Employee Stock Purchase Plan (“ESPP”) using a Black-Scholes option-pricing model on the date of grant. The Black-Scholes option-pricing model requires the use of subjective assumptions including volatility, expected term, risk-free rate, and the fair value of the underlying common stock. For awards that vest based on service conditions, the Company recognizes expense using the straight-line method less estimated forfeitures. Prior to the Company’s initial public offering, the estimated fair value of these awards was determined at the date of grant based upon the estimated fair value of the Company’s common stock. Subsequent to the Company’s initial public offering, the fair value of the common stock is based on observable market prices. As of June 30, 2014, there were no outstanding equity awards with market or performance conditions.

The Company records the expense for stock option grants to non-employees based on the estimated fair value of the stock option using the Black-Scholes option-pricing model. The fair value of non-employee awards is remeasured at each reporting period as the underlying awards vest unless the instruments are fully vested, immediately exercisable and nonforfeitable on the date of grant.

Warrant Liabilities

The Company issued freestanding warrants to purchase shares of common stock and convertible preferred stock in connection with the issuance of convertible notes payable in 2011 and 2012. The Company accounted for these warrants as a liability in the financial statements because either the Company did not have enough authorized shares to satisfy potential exercise of the common stock warrants and the number of shares to be issued upon their exercise was outside the control of the Company, or because the underlying instrument into which the warrants were exercisable (Series D convertible preferred stock) contained deemed liquidation provisions that were outside of the control of the Company. Upon the closing of the initial public offering, warrants to purchase shares of Series D Preferred Stock automatically converted into warrants to purchase shares of common stock. The Company reclassified the warrant liability to stockholders’ equity as the warrants met the definition of an equity instrument.

Prior to the warrants being converted to an equity instrument, the warrants were recorded at fair value using either the Black-Scholes option pricing model, or a binomial lattice model, depending on the characteristics of the warrants at the time of the valuation. The fair value of these warrants was remeasured at each financial reporting period with any changes in fair value being recognized as a component of other income (expense) in the accompanying statements of operations and comprehensive loss. For the three and six months ended June 30, 2013, costs of $0.5 million and $3.3 million were recorded as other expense from the revaluations, respectively. In connection with completion of the initial public offering in November 2013, the Company performed the final remeasurement of the warrant liability.

Net Loss Per Share

Basic net loss per share is calculated by dividing the net loss by the weighted average number of common shares that were outstanding for the period, without consideration for common stock equivalents. Diluted net loss per share is calculated by dividing the net loss by sum of the weighted-average number of dilutive common share equivalents outstanding for the period determined using the treasury-stock method. Dilutive common share equivalents are comprised of convertible preferred stock, preferred stock warrants, common stock warrants, potential ESPP awards, restricted common stock and options outstanding under the Company’s equity incentive plans. Applicable accounting guidance provides that a contract that is reported as an asset or liability for accounting purposes may require an adjustment to the numerator of the diluted earnings per share calculation for any changes in income or loss that would result if the contract had been reported as an equity instrument during the period. Securities are assumed to be converted at the beginning of the period, and the resulting common shares are included in the denominator of the diluted earnings per share calculation for the entire period presented. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the Company’s net loss position.

Potentially dilutive securities not included in the calculation of diluted net loss per share (because inclusion would be anti-dilutive) are as follows (in common stock equivalent shares):


	Three Months Ended June 30,				Six Months Ended June 30,
	2014		2013		2014		2013
Convertible preferred stock outstanding		—		13,148,484		—		11,891,301
Warrants for convertible preferred stock		—		1,426,704		—		1,426,704
Warrants for common stock		1,009,170		271,834		1,009,170		249,306
Common stock options		4,352,181		1,114,453		4,350,888		560,305
ESPP		123,061		—		123,061		—
Restricted common stock subject to repurchase		—		9,113		—		8,371

		5,484,412		15,970,588		5,483,119		14,135,987

Recent Accounting Pronouncements

In April 2014, the Financial Accounting Standards Board (“FASB”) issued an accounting standards update, which includes amendments that change the requirements for reporting discontinued operations and require additional disclosures about discontinued operations. Under the new guidance, only disposals representing a strategic shift in operations - that is, a major effect on the organization’s operations and financial results - should be presented as discontinued operations. Examples include a disposal of a major geographic area, a major line of business, or a major equity method investment. Additionally, the update requires expanded disclosures about discontinued operations that will provide financial statement users with more information about the assets, liabilities, income, and expenses of discontinued operations. The guidance is effective prospectively for fiscal years beginning after December 15, 2014 and interim periods within annual periods beginning on or after December 15, 2015. The Company does not believe the adoption of this standard will have a material impact on its financial position, results of operations or related financial statement disclosures.

In May 2014, the FASB and the International Accounting Standards Board (“IASB”) issued a comprehensive new revenue recognition standard that will supersede existing revenue guidance under U.S. GAAP and International Financial Reporting Standards (“IFRS”). The standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. In doing so, companies will need to use more judgment and make more estimates than under current guidance. These may include identifying performance obligations in the contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. The guidance is effective for annual periods beginning after December 15, 2016, including interim periods within that period. The Company is in the process of assessing the future impact of the adoption of the standard on its financial statements.

Fair Value Measurements

6 Months Ended

Jun. 30, 2014

Fair Value Disclosures [Abstract]

Fair Value Measurements

5. Fair Value Measurements

Authoritative guidance on fair value measurements defines fair value, establishes a consistent framework for measuring fair value, and expands disclosures for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the authoritative guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows:

Level 1: Observable inputs such as quoted prices in active markets.

Level 2: Inputs, other than the quoted prices in active markets, that are observable either directly or indirectly.

Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions.

The following table presents information about the Company’s financial assets measured at fair value on a recurring basis as of June 30, 2014 and December 31, 2013, and indicates the fair value hierarchy of the valuation techniques utilized by the Company to determine such fair value (in thousands):


	June 30, 2014		Fair Value Measurements at June 30, 2014
	June 30, 2014		Level 1		Level 2		Level 3
Assets
Cash equivalents (1)	$	60,470	$	60,470	$	—	$	—
Restricted cash		2,000		2,000		—		—
Commercial paper		28,595		—		28,595		—
Government-sponsored enterprise securities		1,502		—		1,502		—

Total assets	$	92,567	$	62,470	$	30,097	$	—

(1)	Cash equivalents as of June 30, 2014 included money market funds and commercial paper with a maturity of three months or less from the date of purchase.


			Fair Value Measurements at December 31, 2013
	December 31, 2013		Level 1		Level 2		Level 3
Assets
Money market funds	$	115,112	$	115,112	$	—	$	—
Restricted cash		2,050		2,050		—		—
Commercial paper		5,095		—		5,095		—

Total assets	$	122,257	$	117,162	$	5,095	$	—

The Company’s Level 2 financial instruments are valued using market prices on less active markets and model-derived valuations with observable valuation inputs such as interest rates and yield curves. The Company obtains the fair value of Level 2 financial instruments from quoted market price, calculated price or quotes from third-party pricing services. The Company validates through independent valuation testing and review of portfolio valuations provided by the Company’s investment managers. There were no transfers between Level 1 and Level 2 securities during the six months ended June 30, 2014.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Loan Agreements	6 Months Ended
Loan Agreements	Jun. 30, 2014
Debt Disclosure [Abstract]
Loan Agreements	6. Loan Agreements *Silicon Valley Bank Loan* In March 2012, the Company entered into a Loan and Security Agreement with Silicon Valley Bank (“SVB”), drawing a bridge loan in the amount of $5.0 million (the “SVB Bridge Loan”). Subsequent to the closing of the Series D financing, the SVB Bridge Loan was converted into a 24-month term loan (the “SVB Term Loan”) in September 2012. The term loan accrued interest at an annual rate of 4%, with principal and accrued interest payments due monthly throughout the 24-month term. The SVB Term Loan also required a final payment of $0.3 million and a fee of $0.2 million if the loan was prepaid in its entirety prior to the end of the term of the loan. In connection with the SVB Bridge Loan and SVB Term Loan, the Company issued an aggregate of 102,270 warrants to purchase shares of Series D convertible preferred stock at an exercise price of $4.40 per share. In November 2013, in connection with the closing of the initial public offering, all SVB Series D Preferred Stock warrants automatically converted into warrants to purchase 61,033 shares of our Common Stock at a weighted average exercise price of $7.37 per share. In conjunction with the Capital Royalty Term Loan closing in January 2013, all principal, interest due and prepayment fee amounts due under the SVB Term Loan were paid by the Company. *Silicon Valley Bank Revolving Line of Credit* In January 2013, the Company entered into an amended loan agreement with Silicon Valley Bank, making available a revolving line of credit in an amount up to the lesser of $1.5 million or 75% of eligible accounts receivable, and expiring in January 2015. Interest-only payments at a rate of 6% per annum are payable monthly through the maturity date. Loans drawn under the agreement are secured by eligible accounts receivable and proceeds therefrom. Additionally, the terms of the revolving line of credit contain various affirmative and negative covenants. There were no amounts outstanding under this loan as of June 30, 2014 or December 31, 2013. *Capital Royalty Term Loan* In December 2012, the Company executed a Term Loan Agreement (the “Original Term Loan Agreement”) with Capital Royalty Partners II L.P. (“Capital Royalty Partners”) and Capital Royalty Partners II—Parallel Fund “A” L.P. (“CRPPF,” together with Capital Royalty Partners, the “Lenders”), providing the Company access to up to $45.0 million under the arrangement, of which $30.0 million was available in January 2013. An additional amount up to $15.0 million became available upon achievement of a 2013 revenue-based milestone. In January 2013, $30.0 million was drawn under the Original Term Loan Agreement. The loan under the Original Term Loan Agreement accrued interest at an annual rate of 14%. Interest-only payments were due quarterly at March 31, June 30, September 30 and December 31 of each year through December 31, 2015. Thereafter, in addition to interest accrued during the period, quarterly payments were required to include an amount equal to the outstanding principal at December 31, 2015 divided by the remaining number of quarters prior to the maturity of the loan which is December 31, 2017. The Original Term Loan Agreement stipulated prepayment fees of 5% of the outstanding balance of the loan if the loan was repaid prior to April 1, 2014. The prepayment fee was reduced 1% per year for each subsequent year until maturity. In connection with the Original Term Loan Agreement, in January 2013, the Company issued warrants to purchase 271,834 shares of the Company’s Common Stock at an exercise price of $0.02 per share. The warrants were immediately exercisable and expire in January 2023. Because the exercise price of these warrants is nominal, the Company used the fair value of the common stock of $1.61 at December 31, 2012 to value these warrants. The Company also paid a $0.4 million financing fee to the Lenders. The warrants’ fair value of approximately $0.4 million and the financing fee of $0.4 million were recorded as a debt discount. Additionally, the Company paid $0.7 million to a third party for sourcing the Capital Royalty Term Loan, which was recorded as debt issuance cost. The fees and the value of the warrants are amortized to interest expense over the remaining term using the effective interest method. In April 2014, the Company entered into an Amended and Restated Term Loan Agreement (the “Amended and Restated Term Loan Agreement”) with the Lenders and other parties affiliated with Capital Royalty Partners. The Amended and Restated Term Loan Agreement primarily amends the terms of the Original Term Loan Agreement to reduce the borrowing limit to $30.0 million, to reduce the applicable interest rate from 14.0% to 11.5%, and to extend the interest only payment period from December 31, 2015 to March 31, 2018. Interest is payable, at the Company’s option, (i) in cash at a rate of 11.5% per annum or (ii) 9.5% of the 11.5% per annum in cash and 2.0% of the 11.5% per annum is added to the principal of the loan and is subject to accruing interest. Interest-only payments are due quarterly on March 31, June 30, September 30 and December 31 of each year of the interest-only payment period. Thereafter, in addition to interest accrued during the period, the quarterly payments shall include an amount equal to the outstanding principal at March 31, 2018 divided by the remaining number of quarters prior to the end of the term of the loan which is March 31, 2020. The Amended and Restated Term Loan Agreement provides for prepayment fees of 3% of the outstanding balance of the loan if the loan is repaid prior to March 31, 2015. The prepayment fee is reduced by 1% per year for each subsequent year until maturity. Certain affirmative and negative covenants were also amended. The principal financial covenants require that the Company attain minimum annual revenues of $30.0 million in 2014, $50.0 million in 2015, $65.0 million in 2016, $80.0 million in 2017 and $95.0 million thereafter. Concurrently, the Company also entered into a new Term Loan Agreement (the “New Tranche Term Loan Agreement”) with the Lenders and other parties affiliated with Capital Royalty Partners, under which the Company may borrow up to an additional $30.0 million on or before March 31, 2015 at the same interest rate and on the same key terms as the Amended and Restated Term Loan Agreement. Aggregate borrowings outstanding under the Amended and Restated Term Loan Agreement are $30.0 million. Borrowings under the Amended and Restated Term Loan Agreement were used to refinance amounts outstanding under the Original Term Loan Agreement. The present value of the future cash flows under the modified terms described above did not exceed the present value of the future cash flows under the original terms by more than 10%. The Company treated this amendment as a modification and the facility fee of approximately $0.1 million recorded as a discount to the Amended and Restated Term Loan. The facility fee and the remaining balance of debt issuance cost and debt discount of the Original Term Loan are amortized over the remaining term of the Amended and Restated Term Loan using the effective interest method.

Stockholders' Equity

6 Months Ended

Jun. 30, 2014

Equity [Abstract]

Stockholders' Equity

7. Stockholders’ Equity

Shares Reserved for Future Issuance

The following shares of common stock are reserved for future issuance at June 30, 2014:


Common stock warrants outstanding			1,009,170
Stock options issued and outstanding			4,915,926
Authorized for future option grants			2,189,182
Employee stock purchase plan			659,863

			8,774,141

The Company issued 404,476 shares of common stock upon the exercise of stock options and warrants during the six months ended June 30, 2014, and issued 95,007 shares of common stock upon the exercise of stock options and warrants during the year ended December 31, 2013.

In October 2013, the Company adopted the 2013 ESPP. During the three and six months ended June 30, 2014, 125,393 shares of common stock were purchased under the ESPP.

Stock-Based Compensation

The assumptions used in the Black-Scholes option-pricing model are as follows:


	Stock Option
	Three Months Ended June 30,						Six Months Ended June 30,
	2014			2013			2014			2013
Risk-free interest rate		1.9	%		0.8	%		1.9	%		0.9	%
Expected dividend yield		0.0	%		0.0	%		0.0	%		0.0	%
Expected volatility		78.6	%		75.7	%		78.7	%		75.9	%
Expected term (in years)		6.1			5.6			6.1			5.6


	ESPP
	Three Months Ended June 30,					Six Months Ended June 30,
	2014			2013		2014			2013
Risk-free interest rate		0.2	%		—		0.2	%		—
Expected dividend yield		0.0	%		—		0.0	%		—
Expected volatility		62.9	%		—		62.9	%		—
Expected term (in years)		1.3			—		1.3			—

The following table summarizes the allocation of stock compensation expense (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2014		2013		2014		2013
Cost of sales	$	263	$	50	$	626	$	67
Selling, general & administrative		2,816		484		5,819		508
Research and development		452		54		857		69

Total	$	3,531	$	588	$	7,302	$	644

The total stock-based compensation capitalized as part of the cost of inventory was $0.2 million and $0.3 million at June 30, 2014 and December 31, 2013, respectively.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(d),(e))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB TOPIC 4.E)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74512-122707

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21488-112644

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29-31)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6405834&loc=d3e23285-112656

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Preferred Stock
-URI http://asc.fasb.org/extlink&oid=6521494

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21564-112644

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph d
-Article 4

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29, 30, 31
-Article 5

Reference 16: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section E

Reference 17: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Article 4

Reference 18: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section C

Reference 19: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

+ Details

Organization and Basis of Presentation (Policies)

6 Months Ended

Jun. 30, 2014

Accounting Policies [Abstract]

The Company

The Company

Tandem Diabetes Care, Inc. is a medical device company focused on the design, development and commercialization of products for people with insulin-dependent diabetes. Unless the context requires otherwise, the terms the “Company” or “Tandem” refer to Tandem Diabetes Care, Inc.

The Company designed and commercialized its flagship product, the t:slim Insulin Delivery System, or t:slim, based on its proprietary technology platform and unique consumer-focused approach. The U.S. Food and Drug Administration (“FDA”) cleared t:slim in November 2011 and the Company commenced commercial sales of t:slim in the United States in the third quarter of 2012.

Tandem was originally incorporated in the state of Colorado on January 27, 2006 under the name Phluid Inc. On January 7, 2008, the Company was reincorporated in the state of Delaware for the purposes of changing its legal name from Phluid Inc. to Tandem Diabetes Care, Inc. and changing its state of incorporation from Colorado to Delaware.

Basis of Presentation

Basis of Presentation

The Company has prepared the accompanying unaudited condensed financial statements in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and disclosures required by U.S. GAAP for complete financial statements. In the opinion of management, all adjustments which are of a normal and recurring nature, considered necessary for a fair presentation have been included.

Interim financial results are not necessarily indicative of results anticipated for the full year. These unaudited condensed financial statements should be read in conjunction with the Company’s audited financial statements and footnotes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013, from which the balance sheet information herein was derived.

Initial Public Offering

Initial Public Offering

In November 2013, the Company completed its initial public offering of 8,000,000 shares of its common stock at a public offering price of $15.00 per share. Net cash proceeds from the initial public offering were approximately $108.3 million, after deducting underwriting discounts, commissions and estimated offering related transaction costs payable by the Company. In November 2013, the underwriters also exercised their overallotment option and purchased an additional 1,200,000 shares of the Company’s common stock, from which the Company received cash proceeds, net of underwriting discounts and commissions, of approximately $16.7 million. In connection with the closing of the initial public offering, all of the Company’s shares of convertible preferred stock outstanding at the time of the offering were automatically converted into 13,403,747 shares of common stock. In addition, all outstanding preferred stock warrants were automatically converted into warrants to purchase an aggregate of 1,171,352 shares of common stock.

Reverse Stock Splits

Reverse Stock Splits

In October 2013, the Board of Directors approved a 1-for-1.6756 reverse stock split of the Company’s common stock. All share and per share information included in the accompanying unaudited condensed financial statements and notes to the unaudited condensed financial statements give retroactive effect to this reverse stock split of the common stock.

Voluntary Recall

Voluntary Recall

On January 10, 2014, the Company announced a voluntary recall of select lots of cartridges used with the t:slim that may be at risk of leaking. The cause of the recall was identified during the Company’s internal product testing. The recall was expanded on January 20, 2014 to include additional lots of affected cartridges used with the t:slim. The Company incurred approximately $1.7 million in direct costs associated with the recall. The Company recorded a cost of sales charge of approximately $1.3 million in the fourth quarter of 2013 and recorded a cost of sales charge for the remainder in the first quarter of 2014 for affected cartridges shipped in 2014. The Company does not currently expect any further direct financial impact of the recall beyond these costs. The total cost of the recall consisted of approximately $0.7 million associated with the return and replacement of affected cartridges in the field and approximately $1.0 million for the write-off of affected cartridges within the Company’s internal inventory.

Use of Estimates

Use of Estimates

Restricted Cash

Restricted Cash

Restricted cash as of June 30, 2014 represents a $2.0 million minimum cash balance requirement in connection with the Capital Royalty Term Loan (see Note 6 “Loan Agreements”).

Accounts Receivable

Accounts Receivable

Concentration of Credit Risk

Concentration of Credit Risk

The following table summarizes customers who accounted for 10% or more of net accounts receivable:


	June 30, 2014			December 31, 2013
CCS Medical, Inc.		16.8	%		21.4	%
Edgepark Medical Supplies, Inc.		18.9	%		13.1	%

The following table summarizes customers who accounted for 10% or more of sales for the periods presented:


	Three Months Ended June 30,						Six Months Ended June 30,
	2014			2013			2014			2013
CCS Medical, Inc.		14.6	%		N/A			15.7	%		N/A
Edgepark Medical Supplies, Inc.		16.5	%		14.9	%		16.0	%		17.2	%

Fair Value of Financial Instruments

Fair Value of Financial Instruments

Revenue Recognition

Revenue Recognition

•

The evidence of an arrangement generally consists of contractual arrangements with distributors or direct customers.

•

Transfer of title and risk and rewards of ownership are passed upon shipment of the pump to distributors or upon delivery to the customer.

•

The Company considers the overall creditworthiness and payment history of the distributor, customer and the contracted insurance payor in concluding whether collectability is reasonably assured.

Revenue Recognition for Arrangements with Multiple Deliverables

Product Returns

Warranty Reserve

Warranty Reserve

The following table provides a reconciliation of the change in product warranty liabilities through June 30, 2014 (in thousands):


Balance at December 31, 2013	$	1,123
Provision for warranties issued during the period		1,396
Settlements made during the period		(1,617	)

Balance at June 30, 2014	$	902

Stock-Based Compensation

Stock-Based Compensation

Warrant Liabilities

Warrant Liabilities

Net Loss Per Share

Net Loss Per Share

Potentially dilutive securities not included in the calculation of diluted net loss per share (because inclusion would be anti-dilutive) are as follows (in common stock equivalent shares):


	Three Months Ended June 30,				Six Months Ended June 30,
	2014		2013		2014		2013
Convertible preferred stock outstanding		—		13,148,484		—		11,891,301
Warrants for convertible preferred stock		—		1,426,704		—		1,426,704
Warrants for common stock		1,009,170		271,834		1,009,170		249,306
Common stock options		4,352,181		1,114,453		4,350,888		560,305
ESPP		123,061		—		123,061		—
Restricted common stock subject to repurchase		—		9,113		—		8,371

		5,484,412		15,970,588		5,483,119		14,135,987

Recent Accounting Pronouncements

Recent Accounting Pronouncements

Organization and Basis of Presentation - Additional Information (Detail) - USD ($)		1 Months Ended		3 Months Ended	6 Months Ended
	Jan. 10, 2014	Nov. 30, 2013	Oct. 31, 2013	Dec. 31, 2013	Jun. 30, 2014	Jun. 30, 2013
Organization And Basis Of Presentation [Line Items]
Incorporation date					Jan. 27, 2006
Reincorporation date					Jan. 07, 2008
Reverse stock split			1-for-1.6756
Direct costs associated with the recall	$ 1,700,000
Return and replacement of affected cartridges	700,000
Write-off of affected cartridges	$ 1,000,000				$ 163,246	$ 102,946
Initial Public Offering [Member]
Organization And Basis Of Presentation [Line Items]
Shares offered for public offering		8,000,000
Shares offering price per share		$ 15.00
Proceeds from initial public offering		$ 108,300,000
Additional shares issued to underwriters		1,200,000
Net proceeds from additional issuance of stock		$ 16,700,000
Converted number of common stock		13,403,747
Conversion of warrants to common shares		1,171,352
Cost of sales [Member]
Organization And Basis Of Presentation [Line Items]
Direct costs associated with the recall				$ 1,300,000

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) shares in Millions		3 Months Ended	6 Months Ended		12 Months Ended
	Jan. 10, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Dec. 31, 2012
Summary Of Significant Accounting Policies [Line Items]
Restricted cash			$ 2,000,000		$ 2,050,000
Receivables considered as uncollectible, maximum past due days			120 days
Deferred revenue		$ 1,900,000	$ 400,000	$ 1,900,000	200,000	$ 1,900,000
Cost of sales				1,100,000
Revenue recognition hosting period			4 years
Offered period for sales return			30 days
Allowance for product returns			$ 200,000		200,000
Warranty reserve			902,000		1,123,000
Other current liabilities			2,991,219		4,086,196
Other long-term liabilities			$ 861,928		795,640
Product replacement	$ 700,000
Equity awards outstanding			0
Revaluation of warrant liability		$ 453,224		$ 3,283,604
Original Term Loan Agreement [Member]
Summary Of Significant Accounting Policies [Line Items]
Restricted cash			$ 2,000,000
Warranty reserves [Member]
Summary Of Significant Accounting Policies [Line Items]
Warranty reserve			900,000		1,100,000
Other current liabilities			300,000
Other long-term liabilities			600,000
Product replacement			$ 0		$ 300,000
Slim Pump [Member]
Summary Of Significant Accounting Policies [Line Items]
Warranty period offered			4 years
Slim cartridges and infusion sets [Member]
Summary Of Significant Accounting Policies [Line Items]
Warranty period offered			6 months

Loan Agreements - Additional Information (Detail)		1 Months Ended		6 Months Ended
Loan Agreements - Additional Information (Detail)	Apr. 04, 2014	Nov. 30, 2013 $ / shares shares	Jan. 31, 2013 USD ($) $ / Warrant shares	Jun. 30, 2014 USD ($) $ / Warrant shares	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($) $ / shares	Sep. 30, 2012 USD ($)	Mar. 31, 2012 USD ($)
Debt Instrument [Line Items]
Interest-only payments description				Interest-only payments were due quarterly at March 31, June 30, September 30 and December 31 of each year through December 31, 2015.
Minimum annual revenues attainable in 2014				$ 30,000,000
Minimum annual revenues attainable in 2015				50,000,000
Minimum annual revenues attainable in 2016				65,000,000
Minimum annual revenues attainable in 2017				80,000,000
Minimum annual revenues attainable in 2018				95,000,000
Amortization of discount on short-term investment				20,883
SVB Revolving Line of Credit [Member]
Debt Instrument [Line Items]
Available revolving line of credit			$ 1,500,000
Revolving line of credit facility as percentage of accounts receivable			75.00%
Revolving line of credit expiring date			Jan. 31, 2015
Revolving line of credit interest rate			6.00%
Revolving line of credit amount outstanding				$ 0	$ 0
Silicon Valley Bank [Member]
Debt Instrument [Line Items]
Bridge loan								$ 5,000,000
Silicon Valley Bank Term Loan [Member] \| Series D Preferred Stock [Member]
Debt Instrument [Line Items]
Interest rate							4.00%
Loan final payment							$ 300,000
Loan fee							$ 200,000
Accrued interest payments due monthly				The term loan accrued interest at an annual rate of 4%, with principal and accrued interest payments due monthly throughout the 24 month term.
Warrants issued to purchase common stock \| shares				102,270
Warrants exercise price per share \| $ / Warrant				4.40
Converted warrants issued to purchase shares \| shares		61,033
Weighted average exercise price of common stock \| $ / shares		$ 7.37
Original Term Loan Agreement [Member]
Debt Instrument [Line Items]
Interest rate				14.00%
Warrants issued to purchase common stock \| shares			271,834
Warrants exercise price per share \| $ / Warrant			0.02
Available revolving line of credit			$ 30,000,000			$ 45,000,000
Additional loan amount available under agreement			15,000,000
Amount drawn under agreement			$ 30,000,000
Maturity of term loan				Dec. 31, 2017
Prepayment fee percentage				5.00%
Prepayment fee percentage on loan repayment				1.00%
Warrants expiry period			2023-01
Fair value of common stock \| $ / shares						$ 1.61
Warrants fair value recorded as debt discount				$ 400,000
Financing fee of warrant recorded as debt discount				400,000
Debt issuance cost				700,000
Original Term Loan Agreement [Member] \| Capital Royalty Partners [Member]
Debt Instrument [Line Items]
Debt financing fee				400,000
Amended and Restated Term Loan Agreement [Member]
Debt Instrument [Line Items]
Interest rate	11.50%
Available revolving line of credit				$ 30,000,000
Interest-only payments description				Interest-only payments are due quarterly on March 31, June 30, September 30 and December 31 of each year of the interest-only payment period.
Maturity of term loan	Mar. 31, 2020
Prepayment fee percentage	3.00%
Prepayment fee percentage on loan repayment	1.00%
Interest payable as cash	9.50%
Compounded interest payable	2.00%
Present value of the future cash flows				10.00%
Amortization of discount on short-term investment				$ 100,000
Amended and Restated Term Loan Agreement [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Interest rate	11.50%
Interest payment period	Dec. 31, 2015
Amended and Restated Term Loan Agreement [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Interest rate	14.00%
Interest payment period	Mar. 31, 2018
New Tranche Term Loan Agreement [Member] \| March 31, 2015 [Member]
Debt Instrument [Line Items]
Available revolving line of credit				$ 30,000,000

Collaborations - Additional Information (Detail)	3 Months Ended		6 Months Ended		12 Months Ended
Collaborations - Additional Information (Detail)	Jun. 30, 2014 USD ($) Milestone	Jun. 30, 2013 USD ($)	Jun. 30, 2014 USD ($) Milestone	Jun. 30, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2013 USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development cost	$ 3,698,245	$ 2,758,761	$ 7,361,564	$ 5,081,238
Restricted cash	$ 2,000,000		$ 2,000,000			$ 2,050,000
DexCom Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development cost					$ 1,000,000
Number of additional milestone payments \| Milestone	2		2
Additional payment upon achievement of milestones	$ 1,000,000		$ 1,000,000
Reimbursement of development costs			1,000,000
Accrued development costs	0		0			0
Royalty payable	100		100
JDRF Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development cost			3,000,000
Aggregate amount of milestone payment achievements			700,000
Research and development costs offset amount			300,000
Research and development offset amount			100,000	$ 100,000
Restricted cash	$ 0		$ 0			$ 0

Collaborations	6 Months Ended
Collaborations	Jun. 30, 2014
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaborations	8. Collaborations *DexCom Development and Commercialization Agreement* In February 2012, the Company entered into a Development and Commercialization Agreement with DexCom, Inc. (the “DexCom Agreement”) for the purpose of collaborating on the development and commercialization of an integrated system which incorporates the t:slim Insulin Delivery System with DexCom’s proprietary continuous glucose monitoring system. Under the DexCom Agreement, the Company paid DexCom $1.0 million at the commencement of the collaboration which was recorded as research and development cost in 2012 and will make two additional $1.0 million payments upon the achievement of certain milestones. Additionally, the Company will reimburse DexCom up to $1.0 million of its development costs and is solely responsible for its own development costs. The amount accrued for DexCom’s development costs associated with the DexCom Agreement was not material at June 30, 2014 and December 31, 2013. Upon commercialization of the integrated system, and as compensation for the non-exclusive license rights, the Company will also pay DexCom a royalty of $100 for each integrated system sold. *Juvenile Diabetes Research Foundation Collaboration* In January 2013, the Company entered into a research, development and commercialization agreement (“JDRF Agreement”) with the Juvenile Diabetes Research Foundation (“JDRF”) to develop the t:dual Infusion System, a first-of-its-kind, dual-chamber infusion pump for the management of diabetes. According to the terms of the JDRF Agreement, JDRF will provide research funding of up to $3.0 million based on the achievement of research and development milestones, not to exceed research costs incurred by the Company. The research and development milestones are anticipated to be reached by September 2016. Payments the Company receives to fund the collaboration efforts under the terms of the JDRF Agreement will be recorded as restricted cash and current and long term liabilities, and recognized as an offset of research and development expenses straight-line over the remaining months until anticipated completion of the final milestone, only to the extent that the restricted cash is utilized to fund such development activities. As of June 30, 2014, milestone payment achievements totaled $0.7 million, and research and development costs were offset by $0.3 million. The research and development costs were offset by $0.1 million for each of the six-month periods ended June 30, 2014 and 2013. The Company did not have any restricted cash balances related to the JDRF Agreement at June 30, 2014 or December 31, 2013.

Commitments and Contingencies	6 Months Ended
Commitments and Contingencies	Jun. 30, 2014
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	9. Commitments and Contingencies From time to time, the Company may be subject to legal or regulatory proceedings or other matters arising in the ordinary course of business, including proceedings with respect to intellectual property, employment, product liability, and contractual matters. The Company assesses, on a regular basis, the probability of a negative outcome and the range of possible loss based on the developments with respect to these matters. A liability is only recorded in the financial statements if it is believed to be probable that a loss has been incurred and that the amount of the loss can be reasonably estimated. Because of the uncertainties related to the occurrence, amount, and range of loss on any pending proceedings, the Company is currently unable to predict their ultimate outcome, and, with respect to any pending litigation or claim where no liability has been accrued, to make a meaningful estimate of the reasonably possible loss or range of loss that could result from an unfavorable outcome. At June 30, 2014 and December 31, 2013, there were no pending legal or regulatory proceedings for which a negative outcome was considered probable and for which the loss could be reasonably estimated. As a result, no amounts have been accrued with respect to any such proceedings at either date.

Subsequent Event	6 Months Ended
Subsequent Event	Jun. 30, 2014
Subsequent Events [Abstract]
Subsequent Event	10. Subsequent Event In July 2014, the Company paid DexCom $1.0 million as a milestone payment under the DexCom Agreement related to the Company’s submission of a pre-market approval (“PMA”) application for the t:slim G4, which the Company has previously referenced as t:sensor, to the FDA.

Summary of Significant Accounting Policies - Summary of Customers Accounted for 10% or More (Detail)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Accounts receivable [Member] \| CCS Medical, Inc. [Member]
Concentration Risk [Line Items]
Customers accounted for 10% or more			16.80%		21.40%
Accounts receivable [Member] \| Edgepark Medical Supplies, Inc. [Member]
Concentration Risk [Line Items]
Customers accounted for 10% or more			18.90%		13.10%
Sales [Member] \| CCS Medical, Inc. [Member]
Concentration Risk [Line Items]
Customers accounted for 10% or more	14.60%		15.70%
Sales [Member] \| Edgepark Medical Supplies, Inc. [Member]
Concentration Risk [Line Items]
Customers accounted for 10% or more	16.50%	14.90%	16.00%	17.20%

Short-Term Investments - Summary of Estimated Fair Value of Short-Term Investments (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Cash Cash Equivalents And Short Term Investments [Line Items]
Short-term investments, Amortized Cost	$ 30,085	$ 5,095
Short-term investments, Unrealized Gain	13	0
Short-term investments, Unrealized Loss	(1)	0
Short-term investments, Estimated Fair Value	$ 30,097	$ 5,095
Commercial paper [Member]
Cash Cash Equivalents And Short Term Investments [Line Items]
Short-term investments, Maturity (in years)	Less than 1	Less than 1
Short-term investments, Amortized Cost	$ 28,582	$ 5,095
Short-term investments, Unrealized Gain	13	0
Short-term investments, Unrealized Loss	0	0
Short-term investments, Estimated Fair Value	$ 28,595	$ 5,095
Government-sponsored enterprise securities [Member]
Cash Cash Equivalents And Short Term Investments [Line Items]
Short-term investments, Maturity (in years)	1 to 2
Short-term investments, Amortized Cost	$ 1,503
Short-term investments, Unrealized Gain	0
Short-term investments, Unrealized Loss	(1)
Short-term investments, Estimated Fair Value	$ 1,502

Condensed Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2014	Dec. 31, 2013
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	23,455,483	22,925,614
Common stock, shares outstanding	23,455,483	22,925,614

Summary of Significant Accounting Policies - Summary of Reconciliation of Change in Product Warranty Liabilities (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2014 USD ($)
Movement In Standard And Extended Product Warranty Increase Decrease [Roll Forward]
Beginning balance	$ 1,123
Provision for warranties issued during the period	1,396
Settlements made during the period	(1,617)
Ending balance	$ 902

Inventory - Schedule of Inventories (Detail) - USD ($)	Jun. 30, 2014	Dec. 31, 2013
Inventory Disclosure [Abstract]
Raw materials	$ 5,831,000	$ 6,363,000
Work in process	3,413,000	2,169,000
Finished goods	2,307,000	3,535,000
Inventory gross	11,551,000	12,067,000
Less reserve	(430,000)	(1,737,000)
Total	$ 11,121,021	$ 10,330,156

Inventory - Additional Information (Detail) - USD ($) $ in Thousands	Jun. 30, 2014	Dec. 31, 2013
Inventory [Line Items]
Reserve for excess and obsolete inventory	$ 430	$ 1,737
Reserve for excess and obsolete [Member]
Inventory [Line Items]
Reserve for excess and obsolete inventory	$ 0	$ 900

Fair Value Measurements - Schedule of Financial Assets Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2014	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	$ 92,567	$ 122,257
Cash equivalents [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	60,470
Restricted cash [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	2,000	2,050
Commercial paper [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	28,595	5,095
Government-sponsored enterprise securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	1,502
Money market funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets		115,112
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	62,470	117,162
Level 1 [Member] \| Cash equivalents [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	60,470
Level 1 [Member] \| Restricted cash [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	2,000	2,050
Level 1 [Member] \| Money market funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets		115,112
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	30,097	5,095
Level 2 [Member] \| Commercial paper [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	28,595	$ 5,095
Level 2 [Member] \| Government-sponsored enterprise securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	$ 1,502

Fair Value Measurements - Additional Information (Detail)	Jun. 30, 2014 USD ($)
Fair Value Disclosures [Abstract]
Transfer between level 1 and level 2 securities	$ 0

Stockholders' Equity - Schedule of Shares of Common Stock Reserved for Future Issuance (Detail)	Jun. 30, 2014 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	8,774,141
Warrants for common stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	1,009,170
Stock options issued and outstanding [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	4,915,926
Authorized for future option grants [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	2,189,182
Employee stock purchase plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	659,863

Commitments and Contingencies - Additional Information (Detail) - USD ($)	Jun. 30, 2014	Dec. 31, 2013
Commitments And Contingencies Disclosure [Abstract]
Loss contingency accrued	$ 0	$ 0

Subsequent Event - Additional Information (Detail) $ in Millions	Jul. 31, 2014 USD ($)
Subsequent Event [Member] \| DexCom Agreement [Member]
Subsequent Event [Line Items]
Milestone payment made	$ 1.0