Document and Entity Information	6 Months Ended
Document and Entity Information	Jun. 30, 2014	Sep. 12, 2014
Entity Registrant Name	T2 Biosystems, Inc.
Entity Central Index Key	0001492674
Document Type	10-Q
Document Period End Date	Jun. 30, 2014
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		20,040,604
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	Q2

Condensed Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 15,876	$ 30,198
Prepaid expenses and other current assets	202	195
Total current assets	16,078	30,393
Property and equipment, net	1,327	1,118
Restricted cash	340	340
Other assets	2,307	34
Total assets	20,052	31,885
Current liabilities:
Accounts payable	720	943
Accrued expenses	4,222	1,319
Current portion of notes payable	1,769	1,759
Current portion of deferred rent	35	25
Total current liabilities	6,746	4,046
Notes payable, net of current portion	2,411	3,299
Deferred rent, net of current portion	23	45
Warrants to purchase redeemable securities	1,226	1,225
Commitments and contingencies
Redeemable convertible preferred stock	116,625	112,813
Stockholders' deficit:
Common stock, $0.001 par value; 28,254,907 shares authorized at June 30, 2014 and December 31, 2013, respectively; 1,456,508 and 1,411,986 shares issued and outstanding at June 30, 2014 and December 31, 2013, respectively	1	1
Accumulated deficit	(106,980)	(89,544)
Total stockholders' deficit	(106,979)	(89,543)
Total liabilities, redeemable convertible preferred stock and stockholders' deficit	$ 20,052	$ 31,885

Condensed Balance Sheet (Parentheticals) (USD $)	Jun. 30, 2014	Dec. 31, 2013
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	28,254,907	28,254,907
Common stock, shares issued	1,456,508	1,411,986
Common stock, shares outstanding	1,456,508	1,411,986

Condensed Statements of Operations and Comprehensive loss (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Research and grant revenue		$ 120		$ 120
Operating expenses:
Research and development	4,703	3,727	9,768	7,288
Selling, general and administrative	2,446	1,303	4,288	2,343
Total operating expenses	7,149	5,030	14,056	9,631
Loss from operations	(7,149)	(4,910)	(14,056)	(9,511)
Interest expense, net	(80)	(104)	(166)	(209)
Other income (expense), net	(74)		(1)	125
Net loss	(7,303)	(5,014)	(14,223)	(9,595)
Comprehensive loss	(7,303)	(5,014)	(14,223)	(9,595)
Reconciliation of net loss to net loss applicable to common stockholders:
Net loss	(7,303)	(5,014)	(14,223)	(9,595)
Accretion of redeemable convertible preferred stock to redemption value	(1,906)	(1,911)	(3,812)	(3,087)
Net loss applicable to common stockholders	$ (9,209)	$ (6,925)	$ (18,035)	$ (12,682)
Net loss per share applicable to common stockholders - basic and diluted	$ (6.35)	$ (4.95)	$ (12.60)	$ (9.13)
Weighted-average number of common shares used in computing net loss per share applicable to common stockholders - basic and diluted	1,451,124	1,397,603	1,431,542	1,388,953

Condensed Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Operating activities
Net loss	$ (14,223)	$ (9,595)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	299	284
Stock-based compensation expense	505	217
Noncash interest expense	21	22
Change in fair value of warrants	1	(110)
Loss on disposal of asset	(1)
Deferred rent	(13)	(3)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(8)	(146)
Accounts payable	(281)	465
Accrued expenses	1,509	350
Net cash used in operating activities	(12,191)	(8,516)
Investing activities
Purchases of property and equipment	(508)	(420)
Decrease in restricted cash		80
Net cash used in investing activities	(508)	(340)
Financing activities
Proceeds from issuance of redeemable convertible preferred stock, net		39,768
Proceeds from issuance of common stock and stock options exercises, net	96	33
Payment of deferred initial public offering costs	(777)
Payment of deferred financing costs	(50)
Repayments of note payable	(892)	(72)
Net cash (used in) provided by financing activities	(1,623)	39,729
Net (decrease) increase in cash and cash equivalents	(14,322)	30,873
Cash and cash equivalents at beginning of period	30,198	9,709
Cash and cash equivalents at end of period	15,876	40,582
Supplemental disclosures of cash flow information
Cash paid for interest	125	158
Supplemental disclosures of noncash investing and financing activities
Accretion of Series A-1, A-2, B, C, D and E redeemable convertible preferred stock to redemption value	3,812	3,087
Deferred financing costs incurred but unpaid at period end	85
Initial public offering costs incurred but unpaid at period end	$ 1,309

Nature of Business

6 Months Ended

Jun. 30, 2014

Nature of Business

1. Nature of Business

T2 Biosystems, Inc. (the “Company”) was incorporated on April 27, 2006 as a Delaware corporation with operations based in Lexington, Massachusetts. The Company is an in vitro diagnostic company that has developed an innovative and proprietary platform that enables rapid, sensitive and simple direct detection of pathogens, biomarkers and other abnormalities across a variety of unpurified patient sample types. The Company is using its T2 Magnetic Resonance platform (“T2MR”) to develop a broad set of applications aimed at reducing mortality rates, improving patient outcomes and reducing the cost of healthcare by helping medical professionals make targeted treatment decisions earlier. The Company’s initial development efforts target sepsis and hemostasis, areas of significant unmet medical need in which existing therapies could be more effective with improved diagnostics. The Company has completed a pivotal clinical trial for our T2Dx diagnostic instrument (“T2Dx”) and T2Candida panel (“T2Candida”).

Since inception, the Company has devoted substantially all of its efforts to research and development, business planning, recruiting management and technical staff, acquiring operating assets and raising capital.

Liquidity

At June 30, 2014 the Company has generated an accumulated deficit of $107.0 million since inception. The future success of the Company is dependent on its ability to obtain additional capital to develop its product candidates and fund its operations, obtain regulatory clearance for and successfully launch its product candidates and ultimately attain profitable operations. To date, the Company has funded its operations primarily through private placements of its redeemable convertible preferred stock and through debt financing arrangements. On August 12, 2014, the Company completed its initial public offering (“IPO”) whereby the Company sold 5,980,000 shares of its common stock for aggregate net proceeds of approximately $58.7 million (Note 7). As a result of the completion of the IPO and additional liquidity of up to $30.0 million obtained from the loan and security agreement that closed on July 11, 2014 (Note 7), management believes that its cash resources will be sufficient to allow the Company to fund its current operating plan through at least the next twelve months.

The Company is subject to a number of risks similar to other pre-commercial life science companies, including, but not limited to, raising additional capital, development by its competitors of new technological innovations, development and market acceptance of the Company’s product candidates, and protection of proprietary technology.

Summary of Significant Accounting Policies	6 Months Ended
Summary of Significant Accounting Policies	Jun. 30, 2014
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The Company’s financial statements have been prepared in conformity with generally accepted accounting principles in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). Unaudited Interim Financial Information Certain information and footnote disclosures normally included in the Company’s annual financial statement have been condensed or omitted. Accordingly, these interim condensed financial statements should be read in conjunction with the financial statements and notes thereto contained in the Company’s Registration Statement on Form S-1 filed on August 6, 2014, which includes the annual financial statements for the fiscal year ended December 31, 2013. The accompanying interim balance sheet as of June 30, 2014, the statements of operations and comprehensive loss for the three and six months ended June 30, 2014 and 2013, the statements of cash flows for the six months ended June 30, 2014 and 2013 and the related financial data and other information disclosed in these notes are unaudited. The unaudited interim financial statements have been prepared on the same basis as the audited annual financial statements, and, in the opinion of management, reflect all adjustments, consisting of normal recurring adjustments, necessary for the fair presentation of the Company’s financial position as of June 30, 2014, and the results of its operations and its cash flows for the three and six months ended June 30, 2014 and 2013. The results for the three and six months ended June 30, 2014 are not necessarily indicative of the results to be expected for the year ending December 31, 2014, any other interim periods, or any future year or period. Segment Information Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company’s chief operating decision maker is the Chief Executive Officer. The Company views its operations and manages its business in one operating segment, which is the business of developing and, upon regulatory clearance, launching commercially its diagnostic products aimed at reducing mortality rates, improving patient outcomes and reducing the cost of healthcare by helping medical professionals make targeted treatment decisions earlier. Deferred IPO Issuance Costs Deferred initial public offering (“IPO”) issuance costs, which primarily consist of direct and incremental legal and accounting fees relating to the IPO, are capitalized. The deferred IPO issuance costs will be offset against IPO proceeds upon the consummation of the offering (Note 7). As of June 30, 2014, $2.1 million of deferred IPO issuance costs were recorded in other assets and unpaid deferred IPO issuance costs, totaling $1.3 million, were recorded in accrued expenses in the accompanying balance sheet. Reverse Stock Split The Company effected a 1-for-1.7 reverse stock split of its issued and outstanding common stock on July 25, 2014. All share and per share amounts related to issued and outstanding common stock, outstanding options and warrants exercisable for common stock included in these financial statements and notes to the financial statements and have been retroactively adjusted for all periods presented to reflect the reverse stock split, including reclassifying an amount equal to the reduction in par value of common stock to additional paid-in capital. The shares authorized, issued and outstanding of the Company’s redeemable convertible preferred stock are not impacted by the reverse stock split and have not been adjusted. However, the conversion ratios of the Company’s redeemable convertible preferred stock for the purpose of determining the common stock issued upon conversion (Note 7) have been adjusted to reflect the reverse stock split. Net Loss Per Share Basic net loss per share is calculated by dividing net loss applicable to common stockholders, which is net loss plus accretion of redeemable convertible preferred stock to redemption value in the period, by the weighted-average number of common shares outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share is calculated by adjusting the weighted-average number of shares outstanding for the dilutive effect of common stock equivalents outstanding for the period, determined using the treasury-stock method for outstanding stock options and warrants. For purposes of the diluted net loss per share calculation, redeemable convertible preferred stock, warrants to purchase redeemable convertible preferred stock and stock options are considered to be common stock equivalents, but have been excluded from the calculation of diluted net loss per share, as their effect, including the related impact to the numerator of the fair value adjustment of the warrant and the impact to the denominator of the warrant shares, would be anti-dilutive for all periods presented. Therefore, basic and diluted net loss per share applicable to common stockholders were the same for all periods presented. Guarantees As permitted under Delaware law, the Company indemnifies its officers and directors for certain events or occurrences while the officer or director is, or was, serving at the Company’s request in such capacity. The term of the indemnification is for the officer’s or director’s lifetime. The maximum potential amount of future payments the Company could be required to make is unlimited; however, the Company has directors’ and officers’ insurance coverage that limits its exposure and enables it to recover a portion of any future amounts paid. The Company leases office, laboratory and manufacturing space under noncancelable operating leases. The Company has standard indemnification arrangements under the leases that require it to indemnify the landlord against all costs, expenses, fines, suits, claims, demands, liabilities, and actions directly resulting from any breach, violation or nonperformance of any covenant or condition of the Company’s leases. As of June 30, 2014 and December 31, 2013, the Company had not experienced any material losses related to these indemnification obligations, and no material claims with respect thereto were outstanding. The Company does not expect significant claims related to these indemnification obligations and, consequently, concluded that the fair value of these obligations is negligible, and no related reserves were established. Recently Adopted Accounting Pronouncements In June 2014, the FASB issued amended guidance, ASU No 2014-09, Revenue from Contracts with Customers, which is applicable to revenue recognition that will be effective for the Company for the year ended December 31, 2017. The new guidance must be adopted using either a full retrospective approach for all periods presented or a modified retrospective approach. Early adoption is not permitted. The new guidance applies a more principles-based approach to revenue recognition. The Company is evaluating the new guidance and the expected effect on the Company’s condensed financial statements. In June 2014, the FASB issued ASU 2014-10, Development Stage Entities (Topic 915) (“ASU 2014-10”), which removes the definition of a development stage entity from the ASC, thereby removing the financial reporting distinction between development stage entities and other reporting entities. Accordingly, ASU 2014-10 eliminates the requirements for development stage entities to (1) present inception-to-date information in the statements of operations, cash flows and shareholder equity, (2) label financial statements as those of a development stage entity, (3) disclose a description of the development stage activities in which the entity is engaged, and (4) disclose in the first year in which the entity is no longer a development stage entity that in prior years it had been in the development stage. ASU 2014-10 is effective for public business entities for annual periods beginning after December 15, 2014, and interim reporting periods beginning after December 15, 2015, with early adoption permitted. The Company has adopted the provisions of ASU 2014-10 in the June 30, 2014 Quarterly Report on Form 10-Q.

Subsequent Events	6 Months Ended
Subsequent Events	Jun. 30, 2014
Subsequent Events
Subsequent Events	7. Subsequent Events (a) Increase in Authorized Shares On July 1, 2014, the Board approved the following actions, which were approved by the stockholders on the same day: To amend the Company’s 2006 Stock Option Plan to increase the number of shares reserved for future issuance from 2,768,758 to 3,725,224. To approve an amendment to the Restated Certificate of Incorporation to increase the authorized number of shares of common stock from 28,254,907 to 29,880,899. (b) Commitments Loan and Security Agreement On July 11, 2014, the Company entered into a loan and security agreement (“the Note Agreement”) with two lenders to borrow up to $30,000,000 for operations. The Note Agreement allows the Company to borrow amounts in two tranches, up to $20,000,000 (drawn in amounts not less than $10,000,000 upon closing and the remainder drawn in amounts not less than $5,000,000 draws) by December 31, 2014 for tranche A and up to $10,000,000 by June 30, 2015 for tranche B. Borrowings under tranche B are only available to the Company if both of the following conditions are met by June 30, 2015: (a) the Company receives Section 510(k) clearance from the FDA on the Company’s T2Dx and T2Candida products and (b) the Company completes a public or private stock offering, equity raise or strategic partner arrangement resulting in the receipt of at least $30,000,000 in aggregate net proceeds by the Company. The Company received proceeds of $9.8 million under tranche A, net of deferred financing costs. The amounts borrowed under the Note Agreement are collateralized by substantially all of the assets of the Company and bear interest at the one-month LIBOR plus 7.05%, which was 7.20% on the date of issuance. The Company will pay interest only payments on the amounts borrowed under the Note Agreement through January 31, 2016, unless the conditions for borrowings under tranche B are met, in which case the interest only payment period extends to July 31, 2016. After the interest only period, the Company will repay the amounts borrowed in equal monthly installments until the maturity date of July 1, 2019. The Note Agreement requires payment of a final fee of 4.75% of the aggregate original principal of amounts borrowed. In addition, amounts borrowed may be prepaid at the option of the Company in denominations of not less than $1,000,000, and any amounts prepaid are subject to a prepayment premium of 1.5% if prepaid prior to the first anniversary of the borrowing date, 1.0% if prepaid prior to the second anniversary of the borrowing date and after the first anniversary of the borrowing date, and 0.5% if prepaid prior to the maturity date and after the second anniversary of the borrowing date. The Note Agreement does not include any financial covenants, but does contain a subjective acceleration clause whereby upon an event of default, which includes a material adverse change in the business, operations, or conditions (financial or otherwise) of the Company or a material impairment of the prospect of repayment of any portion of the obligations, there can be an immediate acceleration of the borrowings under the Note Agreement. In connection with the closing of the Note Agreement, the Company repaid all amounts outstanding under previously existing borrowing arrangement with a lender, totaling approximately $2.9 million, as of July 11, 2014. Lease Amendment On July 11, 2014, the Company entered into a lease amendment to expand facilities at the Company’s headquarters in Lexington, MA. The term of the lease amendment ends concurrently with the original lease entered into in August 2010 and will increase the monthly base rent by approximately $39,000 per month through December 2015. The Company retains the option to extend the lease for one additional term of two years. (c) Initial Public Offering On August 12, 2014, the Company completed its IPO, whereby the Company sold 5,980,000 shares of its common stock (inclusive of 780,000 shares of common stock sold by the Company pursuant to the full exercise of an overallotment option granted to the underwriters in connection with the offering) at a price of $11.00 per share. The shares began trading on the Nasdaq Global Market on August 7, 2014. The aggregate net proceeds received by the Company from the offering were approximately $58.7 million, after deducting underwriting discounts and commissions and other estimated offering expenses payable by the Company. Upon the closing of the IPO, all outstanding shares of redeemable convertible preferred stock converted into 12,516,298 shares of common stock and warrants exercisable for redeemable convertible preferred stock net exercised into 68,700 shares of common stock, resulting in a reclassification of the related liability for warrants to purchase redeemable convertible preferred stock to additional paid-in capital. In addition, the following other items became effective with the closing of the IPO: (i)On July 25, 2014, the Company filed an amendment to the Certificate of Incorporation to effect the aforementioned stock split, increase the authorized number of shares of common stock from 29,880,899 to 60,000,000, eliminate anti-dilution protection for the preferred stock in the connection with the issuance of common stock as part of the IPO and amend the mandatory conversion provision to remove the minimum price per share and minimum gross proceeds conditions in connection with the IPO. Upon closing of the IPO, the number of authorized shares of common stock of the Company increased to 200,000,000 and the Company is authorized to issue up to 10,000,000 shares of preferred stock. (ii)On July 19, 2014, the Company’s board of directors adopted and, on July 21, 2014, the Company’s stockholders approved, the 2014 Incentive Award Plan (“2014 Plan”), which became effective on August 6, 2014. The 2014 Plan provides for the grant of incentive stock options, nonstatutory stock options, restricted stock awards, restricted stock units, stock appreciation rights and other stock-based awards. The Company’s employees, officers, directors, consultants and advisors are eligible to receive awards under the 2014 Plan. (iii)On July 19, 2014, the Company’s board of directors adopted and, on July 21, 2014, the Company’s stockholders approved, the 2014 Employee Stock Purchase Plan (“2014 ESPP”), which became effective on August 6, 2014. The 2014 ESPP will enable eligible employees to purchase shares of the Company’s common stock at a discount.

Nature of Business (Details) (USD $)			0 Months Ended
Nature of Business (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013	Aug. 12, 2014 Subsequent Event [Member]	Jul. 11, 2014 Subsequent Event [Member] Loan and Security Agreement [Member]
Nature of Business
Deficit accumulated in the development stage	$ 106,980,000	$ 89,544,000
Shares issued upon completion of IPO			5,980,000
Net proceeds received from IPO			58,700,000
Debt instrument
Maximum borrowings available				$ 30,000,000
Period over which cash resources will be sufficient to allow Company to fund current operating plan			12 months

Summary of Significant Accounting Policies (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended	6 Months Ended
	Jul. 25, 2014	Jun. 30, 2014 segment
Segment Information
Number of Operating Segments		1
Deferred IPO issuance costs.
IPO costs deferred		$ 2.1
IPO costs payable		$ 1.3
Reverse stock split
Stock split conversion ratio	0.588

Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Fair value measurements
Transfers of assets from level 1 to 2	$ 0	$ 0
Transfers of assets from level 2 to 1	0	0
Transfer of liabilities from level 1 to 2	0	0
Transfer of liabilities from level 2 to 1	0	0
Transfer of liabilities to or from level 3	0	0
Recurring \| Fair value
Assets:
Restricted cash	340	340
Total assets	16,216	30,538
Liabilities:
Warrants to purchase redeemable securities	1,226	1,225
Total liabilities	1,226	1,225
Recurring \| Fair value \| Cash
Assets:
Cash and cash equivalents	2,557	2,631
Recurring \| Fair value \| Money market funds
Assets:
Cash and cash equivalents	13,319	27,567
Recurring \| Level 1 \| Fair value
Assets:
Restricted cash	340	340
Total assets	16,216	30,538
Recurring \| Level 1 \| Fair value \| Cash
Assets:
Cash and cash equivalents	2,557	2,631
Recurring \| Level 1 \| Fair value \| Money market funds
Assets:
Cash and cash equivalents	13,319	27,567
Recurring \| Level 3 \| Fair value
Liabilities:
Warrants to purchase redeemable securities	1,226	1,225
Total liabilities	$ 1,226	$ 1,225

Fair Value Measurements (Details 2) (Warrants to purchase redeemable convertible preferred stock, USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014
Warrants to purchase redeemable convertible preferred stock
Changes in fair value of preferred stock warrant liability
Beginning balance	$ 1,225
Change in fair value, recorded as a component of other income (expense)	1
Ending balance	$ 1,226

Supplemental Balance Sheet Information (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Accrued expenses
Accrued payroll and compensation	$ 834	$ 496
Accrued professional services	1,769	101
Accrued research and development expenses	1,053	422
Other accrued expenses	566	300
Total accrued expenses	$ 4,222	$ 1,319

Supplemental Balance Sheet Information (Details2) (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Temporary Equity [Line Items]
Redeemable convertible preferred stock	$ 116,625	$ 112,813
Series A-1
Temporary Equity [Line Items]
Redeemable convertible preferred stock	897	874
Par value	$ 0.001	$ 0.001
Shares authorized	282,849	282,849
Shares issued	282,849	282,849
Shares outstanding	282,849	282,849
Liquidation preference	899	877
Series A-2
Temporary Equity [Line Items]
Redeemable convertible preferred stock	7,924	7,724
Par value	$ 0.001	$ 0.001
Shares authorized	1,717,728	1,717,728
Shares issued	1,703,959	1,703,959
Shares outstanding	1,703,959	1,703,959
Liquidation preference	7,942	7,744
Series B
Temporary Equity [Line Items]
Redeemable convertible preferred stock	15,898	15,464
Par value	$ 0.001	$ 0.001
Shares authorized	3,523,765	3,523,765
Shares issued	3,249,877	3,249,877
Shares outstanding	3,249,877	3,249,877
Liquidation preference	15,917	15,485
Series C
Temporary Equity [Line Items]
Redeemable convertible preferred stock	19,701	19,100
Par value	$ 0.001	$ 0.001
Shares authorized	4,085,125	4,085,125
Shares issued	4,055,125	4,055,125
Shares outstanding	4,055,125	4,055,125
Liquidation preference	19,760	19,166
Series D
Temporary Equity [Line Items]
Redeemable convertible preferred stock	28,287	27,357
Par value	$ 0.001	$ 0.001
Shares authorized	5,074,725	5,074,725
Shares issued	5,054,945	5,054,945
Shares outstanding	5,054,945	5,054,945
Liquidation preference	28,361	27,441
Series E
Temporary Equity [Line Items]
Redeemable convertible preferred stock	43,918	42,294
Par value	$ 0.001	$ 0.001
Shares authorized	6,960,967	6,960,967
Shares issued	6,930,967	6,930,967
Shares outstanding	6,930,967	6,930,967
Liquidation preference	$ 44,090	$ 42,490

Stock-Based Compensation (Details 2) (USD $)	3 Months Ended		6 Months Ended
Stock-Based Compensation (Details 2) (USD $)	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Stock-based compensation expense
Stock-based compensation expense	$ 266,000	$ 95,000	$ 505,000	$ 217,000
Total unrecognized compensation costs related to non-vested stock options	2,173,000		2,173,000
Remaining weighted-average period that unrecognized compensation costs are expected to be recognized			3 years 1 month 21 days
Research and Development
Stock-based compensation expense
Stock-based compensation expense	67,000	33,000	123,000	79,000
Selling, General and Administrative
Stock-based compensation expense
Stock-based compensation expense	$ 199,000	$ 62,000	$ 382,000	$ 138,000

Net Loss Per Share (Details)	3 Months Ended		6 Months Ended
Net Loss Per Share (Details)	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Anti-dilutive securities
Anti-dilutive securities excluded from the computation of diluted net loss per share (in shares)	15,011,988	14,271,429	15,011,988	14,271,429
Redeemable Convertible Preferred Stock [Member]
Anti-dilutive securities
Anti-dilutive securities excluded from the computation of diluted net loss per share (in shares)	12,516,298	12,516,298	12,516,298	12,516,298
Options to purchase common shares
Anti-dilutive securities
Anti-dilutive securities excluded from the computation of diluted net loss per share (in shares)	2,348,206	1,607,647	2,348,206	1,607,647
Warrants to purchase redeemable convertible preferred stock
Anti-dilutive securities
Anti-dilutive securities excluded from the computation of diluted net loss per share (in shares)	147,484	147,484	147,484	147,484

Subsequent Events (Detail) (USD $)	6 Months Ended							0 Months Ended		0 Months Ended					0 Months Ended				0 Months Ended
Subsequent Events (Detail) (USD $)	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Jun. 30, 2014 2006 Stock Option Plan Options to purchase common shares	Aug. 12, 2014 Subsequent Event [Member]	Jul. 25, 2014 Subsequent Event [Member]	Jul. 01, 2014 Subsequent Event [Member]	Jul. 11, 2014 Subsequent Event [Member] Facility Expansion Lease [Member] Building [Member] item	Jul. 11, 2014 Subsequent Event [Member] Facility Expansion Lease [Member] Building [Member]	Jul. 11, 2014 Subsequent Event [Member] Loan and Security Agreement [Member] Lender tranche	Jul. 11, 2014 Subsequent Event [Member] Loan and Security Agreement [Member]	Jul. 11, 2014 Subsequent Event [Member] Loan and Security Agreement [Member] Prior To First Anniversary Of Borrowing Date [Member]	Jul. 11, 2014 Subsequent Event [Member] Loan and Security Agreement [Member] Prior to Second Anniversary And After First Anniversary Of Borrowing Date Member	Jul. 11, 2014 Subsequent Event [Member] Loan and Security Agreement [Member] Prior To Maturity Date And After Second Anniversary Of Borrowing Date [Member]	Jul. 11, 2014 Subsequent Event [Member] Loan and Security Agreement [Member] London Interbank Offered Rate (LIBOR) [Member]	Jul. 11, 2014 Subsequent Event [Member] Loan and Security Agreement [Member] Tranche A [Member]	Jul. 11, 2014 Subsequent Event [Member] Loan and Security Agreement [Member] Tranche A [Member]	Jul. 11, 2014 Subsequent Event [Member] Loan and Security Agreement [Member] Tranche B [Member]	Jul. 11, 2014 Subsequent Event [Member] Previously Existing Note Agreement [Member]	Jul. 01, 2014 Subsequent Event [Member] 2006 Stock Option Plan Options to purchase common shares
Subsequent events
Shares reserved for future issuance				2,768,758																3,725,224
Common stock, shares authorized	28,254,907		28,254,907		200,000,000	60,000,000	29,880,899
Number of lenders										2
Maximum borrowings available											$ 30,000,000						$ 20,000,000	$ 10,000,000
Number of tranches										2
Minimum amount of draw upon closing																	10,000,000
Minimum amount of draw after closing																	5,000,000
Minimum net proceeds to be received from stock offering, equity raise, or strategic partner arrangement to allow for borrowing																		30,000,000
Proceeds received on borrowing, net of deferred financing costs																9,800,000
Variable Interest Rate															one-month LIBOR
Basis spread (as a percent)															7.05%
Interest rate on date of issuance (as a percent)											7.20%
Final fee as a percentage of original principal amount of amounts borrowed											4.75%
Minimum amount of denomination for prepayment of borrowings											1,000,000
Prepayment premium (as a percent)												1.50%	1.00%	0.50%
Repayment amount	892,000	72,000																	2,900,000
Increase in monthly base rent									$ 39,000
Number of additional terms available for extension under option								1
Renewal term								2 years