T2 Biosystems (TTOO) 10-K 16 Mar 20 2019 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Mar. 13, 2020	Jun. 28, 2019
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Trading Symbol	TTOO
Entity Registrant Name	T2 Biosystems, Inc.
Entity Central Index Key	0001492674
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	001-36571
Entity Tax Identification Number	20-4827488
Entity Address, Address Line One	101 Hartwell Avenue
Entity Address, City or Town	Lexington
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02421
City Area Code	781
Local Phone Number	761-4646
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, par value $0.001
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Document Annual Report	true
Document Transition Report	false
Entity Common Stock, Shares Outstanding		100,752,864
Entity Public Float			$ 64
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant’s definitive Proxy Statement to be filed with the Securities and Exchange Commission within 120 days after the close of the fiscal year are incorporated by reference into Part III of this report.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 11,033	$ 50,805
Accounts receivable	2,825	1,786
Prepaid expenses and other current assets	1,438	1,340
Inventories	3,599	2,677
Total current assets	18,895	56,608
Property and equipment, net	5,845	7,315
Operating lease right-of-use assets	3,360
Restricted cash	180	180
Other assets	206	206
Total assets	28,486	64,309
Current liabilities:
Notes payable	42,902	42,373
Accounts payable	3,753	744
Accrued expenses and other current liabilities	11,207	6,073
Derivative liability	2,425	2,142
Deferred revenue	285	697
Current portion of lease incentives		268
Total current liabilities	60,572	52,297
Lease incentives, net of current portion		492
Operating lease liabilities, net of current portion	1,873
Deferred revenue, net of current portion	46	133
Commitments and contingencies (see Notes 12 and 13)
Stockholders’ (deficit) equity:
Preferred stock, $0.001 par value; 10,000,000 shares authorized; no shares issued and outstanding
Common stock, $0.001 par value; 200,000,000 shares authorized; 50,651,535 and 44,175,441 shares issued and outstanding at December 31, 2019 and December 31, 2018, respectively	51	44
Additional paid-in capital	342,121	328,514
Accumulated deficit	(376,177)	(317,171)
Total stockholders’ (deficit) equity	(34,005)	11,387
Total liabilities and stockholders’ (deficit) equity	$ 28,486	$ 64,309

Consolidated Balance Sheet (Par

Consolidated Balance Sheet (Parentheticals) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	50,651,535	44,175,441
Common stock, shares outstanding	50,651,535	44,175,441

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue:
Total revenue	$ 8,335	$ 10,500	$ 4,666
Costs and expenses:
Research and development	16,326	14,489	23,733
Selling, general and administrative	27,304	25,697	22,757
Total costs and expenses	60,393	55,590	58,518
Loss from operations	(52,058)	(45,090)	(53,852)
Interest expense, net	(7,348)	(6,682)	(8,907)
Other income, net	400	619	331
Net loss and comprehensive loss	$ (59,006)	$ (51,153)	$ (62,428)
Net loss per share — basic and diluted	$ (1.30)	$ (1.26)	$ (1.94)
Weighted-average number of common shares used in computing net loss per share — basic and diluted	45,507,754	40,558,826	32,131,512
Product [Member]
Revenue:
Total revenue	$ 5,327	$ 4,805	$ 3,440
Costs and expenses:
Cost of product revenue	16,763	15,404	12,028
Research [Member]
Revenue:
Total revenue	563	$ 5,695	$ 1,226
Contribution [Member]
Revenue:
Total revenue	$ 2,445

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' (Deficit) Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Common Stock [Member]Purchase Agreement [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]
Balance at Dec. 31, 2016	$ 39,338	$ 30		$ 242,997	$ (203,689)
Balance (in shares) at Dec. 31, 2016		30,482,712
Stock-based compensation expense	4,790			4,790
Issuance of common stock from vesting of restricted stock, exercise of stock options and employee stock purchase plan	1,059	$ 1		1,058
Issuance of common stock from vesting of restricted stock, exercise of stock options and employee stock purchase plan (in shares)		434,938
Issuance of common stock	18,581	$ 5		18,576
Issuance of common stock (in shares)		5,031,250
Net loss	(62,428)				(62,428)
Balance at Dec. 31, 2017	1,340	$ 36		267,421	(266,117)
Balance (in shares) at Dec. 31, 2017		35,948,900
Cumulative effect of adoption of ASC 606	99				99
Stock-based compensation expense	9,897			9,897
Issuance of common stock from vesting of restricted stock, exercise of stock options and employee stock purchase plan	1,967	$ 1		1,966
Issuance of common stock from vesting of restricted stock, exercise of stock options and employee stock purchase plan (in shares)		1,211,541
Issuance of common stock	49,237	$ 7		49,230
Issuance of common stock (in shares)		7,015,000
Net loss	(51,153)				(51,153)
Balance at Dec. 31, 2018	$ 11,387	$ 44		328,514	(317,171)
Balance (in shares) at Dec. 31, 2018	44,175,441	44,175,441
Stock-based compensation expense	$ 5,458			5,458
Issuance of common stock from vesting of restricted stock, exercise of stock options and employee stock purchase plan	582	$ 1		581
Issuance of common stock from vesting of restricted stock, exercise of stock options and employee stock purchase plan (in shares)		576,245
Issuance of common stock	6,650	$ 6		6,644
Issuance of common stock (in shares)		5,486,500	413,349
Change in fair value of warrants upon modification	264			264
Issuance of warrants	660			660
Net loss	(59,006)				(59,006)
Balance at Dec. 31, 2019	$ (34,005)	$ 51		$ 342,121	$ (376,177)
Balance (in shares) at Dec. 31, 2019	50,651,535	50,651,535

Consolidated Statements of St_2

Consolidated Statements of Stockholders' (Deficit) Equity (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Common Stock [Member]
Issuance costs	$ 175	$ 218	$ 252

Consolidated Statement of Cash

Consolidated Statement of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating activities
Net loss	$ (59,006)	$ (51,153)	$ (62,428)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,197	2,449	2,940
Amortization of operating lease right-of-use assets	1,445
Stock-based compensation expense	5,458	9,897	4,790
Non-cash interest expense	2,407	2,216	2,710
Impairment of property and equipment		683	2,571
(Gain) loss on disposal of property and equipment	(3)	26
Change in fair value of derivative instrument	283	(96)	2,238
Deferred rent		(217)	(115)
Changes in operating assets and liabilities:
Accounts receivable	(1,039)	(1,319)	(140)
Prepaid expenses and other assets	(98)	(570)	125
Inventories, net	(914)	(1,089)	(110)
Accounts payable	2,960	121	(314)
Accrued expenses and other liabilities	3,708	(279)	724
Deferred revenue	(499)	(807)	(709)
Operating lease liabilities	(2,260)
Net cash used in operating activities	(45,361)	(40,138)	(47,718)
Investing activities
Purchases and manufacture of property and equipment	(761)	(593)	(2,476)
Net cash used in investing activities	(761)	(593)	(2,476)
Financing activities
Proceeds from issuance of common stock in public offering, net of offering costs	6,650	49,237	18,640
Proceeds from issuance of shares from employee stock purchase plan and stock option exercises	582	1,967	1,059
Principal repayments of finance leases	(882)	(1,547)	(1,194)
Net cash provided by financing activities	6,350	49,657	18,505
Net increase (decrease) in cash, cash equivalents and restricted cash	(39,772)	8,926	(31,689)
Cash, cash equivalents and restricted cash at beginning of period	50,985	42,059	73,748
Cash, cash equivalents and restricted cash at end of period	11,213	50,985	42,059
Reconciliation of cash, cash equivalents and restricted cash at end of period
Cash and cash equivalents	11,033	50,805	41,799
Restricted cash	180	180	260
Cash, cash equivalents and restricted cash at end of period	11,213	50,985	42,059
Supplemental disclosures of cash flow information
Cash paid for interest	4,659	3,786	3,959
Supplemental disclosures of noncash activities
Transfer of T2 owned instruments and components to inventory	(8)	244	431
Transfer from other liabilities to accrued expenses and other current liabilities	2,400	1,400	585
Right-of-use assets obtained in exchange for new operating lease liabilities	4,805
Change in fair value of warrants issued and modified	924
Purchases of property and equipment included in accounts payable and accrued expenses	$ 107	$ 80	189
Public offering costs unpaid at year end			$ 59

Nature of Business

Nature of Business	12 Months Ended
	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of Business	1. Nature of Business T2 Biosystems, Inc. (the “Company” or “T2”) was incorporated on April 27, 2006 as a Delaware corporation with operations based in Lexington, Massachusetts. The Company is an in vitro The Company has devoted substantially all of its efforts to research and development, business planning, recruiting management and technical staff, acquiring operating assets, raising capital, and, most recently, the commercialization and improvement of its existing products. Liquidity and Going Concern At December 31, 2019, the Company has cash and cash equivalents of $11.0 million, an accumulated deficit of $376.2 million, a stockholders’ deficit of $34.0 million, and has experienced cash outflows from operating activities over the past years. The future success of the Company is dependent on its ability to successfully commercialize its products, obtain regulatory clearance for and successfully launch its future product candidates, obtain additional capital and ultimately attain profitable operations. Historically, the Company has funded its operations primarily through its August 2014 initial public offering, its December 2015 public offering, its September 2016 private investment in public equity (“PIPE”) financing, its September 2017 public offering, its June 2018 public offering, its July 2019 establishment of an Equity Distribution Agreement and Equity Purchase Agreement, private placements of redeemable convertible preferred stock and through debt financing arrangements The Company is subject to a number of risks similar to other newly commercial life science companies, including, but not limited to commercially launching the Company’s products, development and market acceptance of the Company’s product candidates, development by its competitors of new technological innovations, protection of proprietary technology, and raising additional capital. Having obtained authorization from the FDA to market the T2Dx, T2Candida, and T2Bacteria, the Company has incurred significant commercialization expenses related to product sales, marketing, manufacturing and distribution. The Company may seek to fund its operations through public equity, private equity or debt financings, as well as other sources. However, the Company may be unable to raise additional funds or enter into such other arrangements when needed, on favorable terms, or at all. The Company’s failure to raise capital or enter into such other arrangements if and when needed would have a negative impact on the Company’s business, results of operations, financial condition and the Company’s ability to develop and commercialize T2Dx, T2Candida, T2Bacteria and other product candidates. Pursuant to the requirements of Accounting Standards Codification (“ASC”) 205-40, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern The Company believes that its existing cash and cash equivalents at December 31, 2019, along with sales of its common stock since December 31, 2019 pursuant to the Company’s recently established Equity Distribution Agreement (the “Sales Agreement”) with Canaccord Genuity LLC, as agent (“Canaccord”) of $29.4 million through March 13, 2020, and additional funding available through the Sales Agreement and Purchase Agreement with Lincoln Park Capital Fund, LLC (“Lincoln Park”) (the “Purchase Agreement”) (Note 7) in the future, will be sufficient to allow the Company to fund its current operating plan assuming availability of funds through those agreements. However, as certain elements of the Company’s operating plan are outside of the Company’s control, including the ability to sell shares under the Sales Agreement and the Purchase Agreement, those elements cannot be considered probable. Under ASC 205-40, the future receipt of potential funding from the Company’s Co-Development partners and other resources cannot be considered probable at this time because none of the plans are entirely within the Company’s control. The Purchase Agreement may not be readily available for use if the stock price remains below $1.00 (Note 7). The Term Loan Agreement with CRG Servicing LLC (“CRG”) (Note 6) requires us to achieve certain annual revenue targets, whereby the Company is required to pay double the amount of any shortfall as an acceleration of principal payments and maintain a minimum cash balance of $5.0 million. The Term Loan Agreement with CRG is classified as a current liability on the balance sheet at December 31, 2019, based on the Company’s consideration of the probability of violating the minimum liquidity covenant. Should the Company fall short of the revenue target, it would seek a waiver of this provision. There can be no assurances that the Company would be successful in obtaining a waiver. These conditions raise substantial doubt regarding the Company’s ability to continue as a going concern for a period of one year after the date that the financial statements are issued. Management's plans to alleviate the conditions that raise substantial doubt include raising additional funding, earning payments pursuant the Company’s Co- Development agreements, delaying certain research projects and capital expenditures and eliminating certain future operating expenses in order to fund operations at reduced levels for the Company to continue as a going concern for a period of 12 months from the date the financial statements are issued. Management has concluded the likelihood that its plan to successfully obtain sufficient funding from one or more of these sources or adequately reduce expenditures, while reasonably possible, is less than probable. Accordingly, the Company has concluded that substantial doubt exists about the Company’s ability to continue as a going concern for a period of at least 12 months from the date of issuance of these consolidated financial statements. The accompanying financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the ordinary course of business. The financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of the uncertainties described above.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation and Consolidation The Company’s financial statements have been prepared in conformity with accounting principles generally accepted 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 and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). The Company’s consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary, T2 Biosystems Securities Corporation. All intercompany balances and transactions have been eliminated. Use of Estimates The preparation of the Company’s consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. The Company utilizes certain estimates in the determination of the accounts receivable allowance, the excess and obsolete inventory, the net realizable value of inventory, the fair value of its stock options, as well as restricted stock units that have market conditions, deferred tax valuation allowances, revenue recognition, expenses relating to research and development contracts, accrued expenses, the fair value of a derivative liability, the fair value of warrants and classification of the value of instrument raw material and work-in-process inventory between inventory and property and equipment. The Company bases its estimates on historical experience and other market ‑ 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 ‑ Geographic Information The Company sells its products domestically and internationally. International sales to a single country did not exceed 10% of total revenue in any year. Total international sales were approximately $2.8 million or 34% of total revenue in 2019, $2.2 million or 21% of total revenue in 2018 and $0.9 million or 19% of total revenue in 2017. As of December 31, 2019 and 2018, the Company had outstanding receivables of $1.2 million and $0.9 million, respectively, from customers located outside of the U.S. Off ‑ The Company has no significant off-balance sheet risks, such as foreign exchange contracts, option contracts, or other foreign hedging arrangements. Cash and cash equivalents are financial instruments that potentially subject the Company to concentrations of credit risk. At December 31, 2019 and 2018, substantially all of the Company’s cash was deposited in accounts at one financial institution, with a portion invested in money market funds that are invested in short-term U.S. government agency securities. The Company maintains its cash deposits, which at times may exceed the federally insured limits, with a large financial institution and, accordingly, the Company believes such funds are subject to minimal credit risk. For the year ended December 31, 2019, the Company derived approximately 19% of its total revenue from one customer, 11% of its total revenue from a second customer, and 8% of its total revenue from a third customer. For the year ended December 31, 2018, the Company derived approximately 29% of its total revenue from one customer, 15% of its total revenue from a second customer and 10% of its total revenue from a third customer. For the year ended December 31, 2017, the company derived 19% of its total revenue from one customer and 10% of its revenue from a second customer. At December 31, 2019, the Company had two customers that represented 27% and 10%, respectively, of its accounts receivable balance. At December 31, 2018, the Company had two customers that represented 25% and 22%, respectively, of its accounts receivable balance. The Company relies on single-source suppliers for some components and materials used in its products and product candidates. The Company has entered into supply agreements with most of its suppliers to help ensure component availability and flexible purchasing terms with respect to the purchase of such components. While the Company believes replacement suppliers exist for all components and materials obtained from single sources, establishing additional or replacement suppliers for any of these components or materials, if required, may not be accomplished quickly. Even if the Company is able to find a replacement supplier, the replacement supplier would need to be qualified and may require additional regulatory authority approval, which could result in further delay. If third-party suppliers fail to deliver the required commercial quantities of materials on a timely basis and at commercially reasonable prices, and the Company is unable to find one or more replacement suppliers capable of production at a substantially equivalent cost in substantially equivalent volumes and quality on a timely basis, the continued commercialization of products, the supply of products to customers and the development of any future products would be delayed, limited or prevented, which could have an adverse impact on the business. Cash Equivalents Cash equivalents include all highly liquid investments with original maturities of 90 days or less. Cash equivalents consist of money market funds invested in short-term U.S. government agency securities as of December 31, 2019 and 2018. Accounts Receivable The Company’s accounts receivable consists of amounts due from product sales to commercial customers and from research and development arrangements with partners. At each reporting period, management reviews all outstanding balances to determine if the facts and circumstances of each customer relationship indicate the need for a reserve. The Company does not require collateral and did not have an allowance for doubtful accounts at December 31, 2019 or 2018. Inventories Inventories are stated at the lower of cost or net realizable value. The Company determines the cost of its inventories, which includes amounts related to materials, direct labor, and manufacturing overhead, on a first-in, first-out basis. The Company performs an assessment of the recoverability of capitalized inventory during each reporting period, and writes down any excess and obsolete inventories to their realizable value in the period in which the impairment is first identified. Shipping and handling costs incurred for inventory purchases are capitalized and recorded upon sale in cost of product revenues in the consolidated statements of operations and comprehensive loss or are included in the value of T2-owned instruments and components, a component of property and equipment, net, and depreciated. The Company capitalizes inventories in preparation for sales of products when the related product candidates are considered to have a high likelihood of regulatory clearance, which for the T2Dx Instrument, T2Candida and T2Bacteria was upon the achievement of regulatory clearance, and the related costs are expected to be recoverable through sales of the inventories. In addition, the Company capitalizes inventories related to the manufacture of instruments that have a high likelihood of regulatory clearance, which for the T2Dx Instrument was upon the achievement of regulatory clearance, and will be retained as the Company’s assets, upon determination that the instrument has alternative future uses. In determining whether or not to capitalize such inventories, the Company evaluates, among other factors, information regarding the product candidate’s status of regulatory submissions and communications with regulatory authorities, the outlook for commercial sales and alternative future uses of the product candidate. Costs associated with development products prior to satisfying the inventory capitalization criteria are charged to research and development expense as incurred. The Company classifies instruments that are Company-owned, as a component of property and equipment. Raw material and work-in-process inventories that are expected to be used to produce Company-owned instruments, based on the Company’s business model and forecast, are also classified as property and equipment. Company-owned instruments are instruments that are manufactured and placed with customers in connection with reagent rental agreements, or are used for internal purposes. The components of inventory consist of the following (in thousands): December 31, December 31, 2019 2018 Raw materials $ 1,617 $ 639 Work-in-process 1,227 1,713 Finished goods 755 325 Total inventories, net $ 3,599 $ 2,677 Fair Value Measurements The Company is required to disclose information on all assets and liabilities reported at fair value that enables an assessment of the inputs used in determining the reported fair values. ASC 820, Fair Value Measurements and Disclosures Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability, and are developed based on the best information available in the circumstances. The fair value hierarchy applies only to the valuation inputs used in determining the reported fair value of the investments and is not a measure of the investment credit quality. The hierarchy defines three levels of valuation inputs: Level 1 — Quoted unadjusted prices for identical instruments in active markets. Level 2 — Quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model ‑ Level 3 — Model derived valuations in which one or more significant inputs or significant value drivers are unobservable, including assumptions developed by the Company. The fair value hierarchy prioritizes valuation inputs based on the observable nature of those inputs. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability (Note 3). For certain financial instruments, including accounts receivable, prepaid expenses and other current assets, accounts payable and accrued expenses, the carrying amounts approximate their fair values as of December 31, 2019 and 2018 because of their short-term nature. At December 31, 2019 and 2018, the fair value of the derivative liability was determined using Level 3 inputs using a valuation model that includes assumptions from the Company (Note 6). Property and Equipment Property and equipment are recorded at cost and depreciated over their estimated useful lives using the straight‑line method. Property and equipment, net, includes assets under capital leases. Property and equipment includes raw materials and work-in-process inventory that are expected to be used or used to produce T2-owned instruments based on the Company’s business model and forecast, and finished instruments that will be used for internal research and development, clinical studies or reagent rental agreements with customers. Completed T2-owned instruments are placed in service once installation procedures are completed. Construction in progress is primarily comprised of equipment that has not been placed in service. Leases The Company adopted Topic 842, Leases Leases At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present. Leases with a term greater than one year are recognized on the balance sheet as right-of-use assets, lease liabilities and long-term lease liabilities. The Company has elected not to recognize on the balance sheet leases with terms of one year or less. Operating lease liabilities and their corresponding right-of-use assets are recorded based on the present value of lease payments over the expected remaining lease term. However, certain adjustments to the right-of-use asset may be required for items such as prepaid or accrued lease payments. The interest rate implicit in lease contracts is typically not readily determinable. As a result, the Company utilizes its incremental borrowing rates, which are the rates incurred to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment. In accordance with the guidance in ASC 842, components of a lease should be split into three categories: lease components (e.g. land, building, etc.), non-lease components (e.g. common area maintenance, consumables, etc.), and non-components (e.g. property taxes, insurance, etc.). Subsequently, the fixed and in-substance fixed contract consideration (including any related to non-components) must be allocated based on the respective relative fair values to the lease components and non-lease components. The Company made the policy election to not separate lease and non-lease components. Each lease component and the related non-lease components are accounted for together as a single component. Revenue Recognition The Company adopted ASC 606, Revenue from Contracts with Customers Revenue Recognition The Company generates revenue from the sale of instruments, consumable diagnostic tests, related services, reagent rental agreements, research and development agreements with third parties and government contributions. Pursuant to ASC 606, revenue is recognized when a customer obtains control of promised goods or services. The amount of revenue recognized reflects the consideration the Company expects to be entitled to receive in exchange for these goods and services. Once a contract is determined to be within the scope of ASC 606 at contract inception, the Company reviews the contract to determine which performance obligations the Company must deliver and which of these performance obligations are distinct. The Company recognizes as revenues the amount of the transaction price that is allocated to the respective performance obligation when the performance obligation is satisfied or as it is satisfied. Generally, the Company's performance obligations are transferred to customers at a point in time, typically upon shipment, or over time, as services are performed. Most of the Company’s contracts with distributors in geographic regions outside the United States contain only a single performance obligation; whereas, most of the Company’s contracts with direct sales customers in the United States contain multiple performance obligations. For these contracts, the Company accounts for individual performance obligations separately if they are distinct. The transaction price is allocated to the separate performance obligations on a relative standalone selling price basis. Excluded from the transaction price are sales tax and other similar taxes which are presented on a net basis. Product revenue is generated by the sale of instruments and consumable diagnostic tests predominantly through the Company’s direct sales force in the United States and distributors in geographic regions outside the United States. The Company does not offer product return or exchange rights (other than those relating to defective goods under warranty) or price protection allowances to its customers, including its distributors. Payment terms granted to distributors are the same as those granted to end-user customers and payments are not dependent upon the distributors’ receipt of payment from their end-user customers. The Company either sells instruments to customers and international distributors, or retains title and places the instrument at the customer site pursuant to a reagent rental agreement. When an instrument is purchased by a customer, the Company recognizes revenue when the related performance obligation is satisfied (i.e. when the control of an instrument has passed to the customer; typically, at shipping point). When the instrument is placed under a reagent rental agreement, the Company’s customers generally agree to fixed term agreements, which can be extended, and incremental charges on each consumable diagnostic test purchased. Revenue from the sale of consumable diagnostic tests is recognized upon shipment. The transaction price from consumables purchases (under a reagent rental agreement) is allocated between the lease of the instrument (under a contingent rent methodology as provided for in ASC 842), and the consumables when related performance obligations are satisfied, as a component of lease and product revenue, and is included as Instrument Rentals in the below table. Revenue associated with reagent rental consumables purchases is currently classified as variable consideration and constrained until a purchase order is received and related performance obligations have been satisfied. Shipping and handling costs billed to customers in connection with a product sale are recorded as a component of the transaction price and allocated to product revenue in the consolidated statements of operations and comprehensive loss as they are incurred by the Company in fulfilling its performance obligations. Direct sales of instruments include warranty, maintenance and technical support services typically for one year following the installation of the purchased instrument (“Maintenance Services”). Maintenance Services are separate performance obligations as they are service based warranties and are recognized on a straight-line basis over the service delivery period. After the completion of the initial Maintenance Services period, customers have the option to renew or extend the Maintenance Services typically for additional Fees paid to member-owned group purchasing organizations (“GPOs”) are deducted from related product revenues. The Company warrants that consumable diagnostic tests will be free from defects, when handled according to product specifications, for the stated life of the product. To fulfill valid warranty claims, the Company provides replacement product free of charge. Accordingly, the Company accrues warranty expense associated with the estimated defective rates of the consumable diagnostic tests. Revenue earned from activities performed pursuant to research and development agreements is reported as research revenue in the consolidated statements of operations and comprehensive loss, and is recognized over time using an input method as the work is completed. The related costs are expensed as incurred as research and development expense. The timing of receipt of cash from the Company’s research and development agreements generally differs from when revenue is recognized. Milestones are contingent on the occurrence of future events and are considered variable consideration being constrained until the Company believes a significant revenue reversal will not occur. Refer to Note 15 for further details regarding the Company’s research and development arrangements. The Company adopted ASU No. 2018-08, Not-For-Profit Entities – Clarifying the Scope and the Accounting Guidance for Contributions Received and Contributions Made (“ASU 2018-08”) on January 1, 2019. According to ASU 2018-08, g The reported results for 2019 reflect the application of ASU 2018-08 as Disaggregation of Revenue The Company disaggregates revenue from contracts with customers by type of products and services, as it best depicts how the nature, amount, timing and uncertainty of revenue and cash flows are affected by economic factors. The following table disaggregates total revenue by major source (in thousands): 2019 2018 Product Revenue Instruments $ 2,280 $ 1,895 Consumables 2,863 2,387 Instrument Rentals 184 523 Total Product Revenue 5,327 4,805 Research Revenue 563 5,695 Contribution Revenue 2,445 — Total Revenue $ 8,335 $ 10,500 Remaining Performance Obligations Remaining performance obligations represent the transaction price of firm orders for which work has not been performed or goods and services have not been delivered. As of December 31, 2019 and 2018, the aggregate amount of transaction price allocated to remaining performance obligations for contracts with an original duration greater than one year was $0.2 million and $3.7 million, respectively, of which $3.0 million is constrained revenue in 2018. We do not disclose the value of unsatisfied performance obligations for (i) contracts with an original expected length of one year or less and (ii) contracts for which we recognize revenue at the amount to which we have the right to invoice for services performed. The Company expects to recognize revenue on the remaining performance obligations over the next 2 years. Significant Judgments Certain contracts with customers include promises to transfer multiple products and services to a customer. Determining whether products and services are considered distinct performance obligations that should be accounted for separately versus together may require significant judgment. Once we determine the performance obligations, the Company determines the transaction price, which includes estimating the amount of variable consideration, based on the most likely amount, to be included in the transaction price, if any. We then allocate the transaction price to each performance obligation in the contract based on a relative stand-alone selling price method. The corresponding revenue is recognized as the related performance obligations are satisfied as discussed in the revenue categories above. Judgment is required to determine the standalone selling price for each distinct performance obligation. We determine standalone selling price based on the price at which the performance obligation is sold separately. If the standalone selling price is not observable through past transactions, we estimate the standalone selling price taking into account available information such as market conditions and the expected costs and margin related to the performance obligations. Contract Assets and Liabilities The Company did not record any contract assets at December 31, 2019 and 2018. The Company’s contract liabilities consist of upfront payments for research and development contracts and maintenance services on instrument sales. We classify these contract liabilities in deferred revenue as current or noncurrent based on the timing of when we expect to recognize revenue. At December 31, 2019 and 2018, the Company had contract liabilities of $0.2 million and $0.6 million, respectively. Revenue recognized in the year-ended December 31, 2019 relating to contract liabilities at December 31, 2018 was $0.6 million, and related to performance of research and development services and straight-line revenue recognition associated with maintenance agreements. Cost to Obtain and Fulfill a Contract The Company does not meet the recoverability criteria to capitalize costs to obtain or fulfill instrument purchases. Reagent rental agreements do not meet the recoverability criteria to capitalize costs to obtain the contracts and the costs to fulfill the contracts are under the scope of ASC 842. At the end of each reporting period, the Company assesses whether any circumstances have changed to meet the criteria for capitalization. The Company did not incur any expenses to obtain research and development agreements and costs to fulfill those contracts do not generate or enhance resources of the entity. As such, no costs to obtain or fulfill contracts have been capitalized at period end. Cost of Product Revenue Cost of product revenue includes the cost of materials, direct labor and manufacturing overhead costs used in the manufacture of consumable diagnostic tests sold to customers and related license and royalty fees. Cost of product revenue also includes depreciation on revenue generating T2Dx instruments that have been placed with customers under reagent rental agreements; costs of materials, direct labor and manufacturing overhead costs on the T2Dx instruments sold to customers; and other costs such as customer support costs, royalties and license fees, warranty and repair and maintenance expense on the T2Dx instruments that have been placed with customers under reagent rental agreements. Research and Development Costs Costs incurred in the research and development of the Company’s product candidates are expensed as incurred. Research and development expenses consist of costs incurred in performing research and development activities, including activities associated with performing services under research revenue arrangements, costs associated with the manufacture of developed products and include salaries and benefits, stock compensation, research‑related facility and overhead costs, laboratory supplies, equipment and contract services. Impairment of Long-lived Assets The Company reviews long‑lived assets, including capitalized T2 owned instruments and components, for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If indications of impairment exist, projected future undiscounted cash flows associated with the asset or asset group are compared to the carrying amount to determine whether the asset’s value is recoverable. During this review, the Company reevaluates the significant assumptions used in determining the original cost and estimated lives of long‑lived assets. Although the assumptions may vary from asset to asset, they generally include operating results, changes in the use of the asset, cash flows and other indicators of value. Management then determines whether the remaining useful life continues to be appropriate or whether there has been an impairment of long‑lived assets based primarily upon whether expected future undiscounted cash flows are sufficient to support the assets’ recovery. If impairment exists, the Company would adjust the carrying value of the asset to fair value, generally determined by a discounted cash flow analysis. If the carrying value of the asset exceeds such projected undiscounted cash flows, the asset will be written down to its estimated fair value. Comprehensive Loss Comprehensive loss is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non‑owner sources. Comprehensive loss consists of net loss and other comprehensive loss, which includes certain changes in equity that are excluded from net loss. The Company’s comprehensive loss equals reported net loss for all periods presented. Stock-Based Compensation The Company records stock‑based compensation for options granted to employees and to members of the Board of Directors for their services on the Board of Directors, based on the grant date fair value of awards issued, and the expense is recorded on a straight‑line basis over the requisite service period, which is generally four years. The Company accounts for non‑employee stock‑based compensation arrangements based upon the fair value of the consideration received or the equity instruments issued, whichever is more reliably measurable. The measurement date for non‑employee awards is generally the date that the performance of services required for the non‑employee award is complete. Stock‑based compensation costs for non‑employee awards is recognized as services are provided, which is generally the vesting period, on a straight‑line basis. The Company records the expense for stock option grants that vest upon achievement of performance-based milestones using the accelerated attribution method over the remaining service period when management determines that achievement of the performance-based milestone is probable. Management evaluates when the achievement of a performance-based milestone is probable based on the relative satisfaction of the performance conditions as of the reporting date. The Company expenses restricted stock awards and restricted stock units based on the fair value of the award on the date of issuance, on a straight‑line basis over the associated service period of the award. The Company uses the Black‑Scholes‑Merton option pricing model to determine the fair value of stock options. The use of the Black‑Scholes‑Merton option‑pricing model requires management to make assumptions with respect to the expected term of the option, the expected volatility of the common stock consistent with the expected life of the option, risk‑free interest rates and expected dividend yields of the common stock. The expected term was determined according to the simplified method, which is the average of the vesting tranche dates and the contractual term. Due to the lack of company specific historical and implied volatility data resulting from the Company’s limited public market trading history, prior to August 2018, the Company had based its estimate of expected volatility primarily on the historical volatility of a group of similar companies that are publicly traded. For these analyses, companies with comparable characteristics are selected, including enterprise value and position within the industry, and with historical share price information sufficient to meet the expected life of the stock‑based awards. The Company computes the historical volatility data using the daily closing prices for the selected companies’ shares during the equivalent period of the calculated expected term of its stock‑based awards. As of August 2018, the Company determined that a sufficient amount of historical information regarding the volatility of its stock price was available and estimated expected volatility based on the historical volatility of the Company’s stock using the daily closing prices. The risk‑free interest rate is determined by reference to U.S. Treasury zero‑coupon issues with remaining maturities similar to the expected term of the options. The Company has not paid, and does not anticipate paying, cash dividends on shares of common stock; therefore, the expected dividend yield is assumed to be zero. The Company has elected an accounting policy to estimate forfeitures at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from those estimates. The Company uses a Monte Carlo simulation to determine the fair value of restricted stock units with market conditions on the date of grant. The compensation cost for restricted stock units with market conditions is being recorded over the derived service period. If a market condition is achieved prior to completion of the derived service period, the remaining compensation cost will be recognized immediately. Refer to Note 8 for further details on the Company’s stock-based compensation plan. Income Taxes The Company provides for income taxes using the liability method. The Company provides deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the Company’s financial statement carrying amounts and the tax basis of assets and liabilities using enacted tax rates expected to be in effect in the years in which the differences are expected to reverse. A valuation allowance is provided to reduce the deferred tax assets to the amount that will more likely than not be realized. The Company applies ASC 740 Income Taxes The Tax Cuts and Jobs Act (the “Act”) was enacted on December 22, 2017. The Act reduces the US federal corporate tax rate from 35% to 21%, requires companies to pay a one-time transition tax on earnings of certain foreign subsidiaries that were previously tax deferred and creates new taxes on certain foreign sourced earnings. On December 22, 2017, the Securities and Exchange Commission (the “SEC”) issued guidance under Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act (“SAB 118”) directing taxpayers to consider the impact of the U.S. legislation as “provisional” when it does not have the necessary information available, prepared or analyzed (including computations) in reasonable detail to complete its accounting for the change in tax law. As of December 31, 2018, the Company did not recognize a provisional amount for the transition tax. For the year ended December 31, 2019, the Company recognized no transition tax, have re

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements The Company measures the following financial assets at fair value on a recurring basis. There were no transfers between levels of the fair value hierarchy during any of the periods presented. The following tables set forth the Company’s financial assets and liabilities carried at fair value categorized using the lowest level of input applicable to each financial instrument as of December 31, 2019 and 2018 (in thousands): Quoted Prices in Active Significant Markets for Other Significant Balance at Identical Observable Unobservable December 31, Assets Inputs Inputs 2019 (Level 1) (Level 2) (Level 3) Assets: Cash $ 6,732 $ 6,732 $ — $ — Money market funds 4,301 4,301 — — Restricted cash 180 180 — — $ 11,213 $ 11,213 $ — $ — Liabilities: Derivative liability $ 2,425 $ — $ — $ 2,425 $ 2,425 $ — $ — $ 2,425 Quoted Prices in Active Significant Markets for Other Significant Balance at Identical Observable Unobservable December 31, Assets Inputs Inputs 2018 (Level 1) (Level 2) (Level 3) Assets: Cash $ 6,868 $ 6,868 $ — $ — Money market funds $ 43,937 43,937 — — Restricted cash $ 180 180 — — $ 50,985 $ 50,985 $ — $ — Liabilities: Derivative liability $ 2,142 $ — $ — $ 2,142 $ 2,142 $ — $ — $ 2,142 The Company maintains certificates of deposit, classified as restricted cash, for $0.2 million (Note 4). The Company’s Term Loan Agreement with CRG (the “Term Loan Agreement”) (Note 6) contains certain provisions that change the underlying cash flows of the debt instrument, including acceleration of the obligations under the Term Loan Agreement under an event of default. In addition, under certain circumstances, a default interest rate of an additional 4.0% per annum will apply at the election of CRG on all outstanding obligations during the occurrence and continuance of an event of default. The Company concluded that these features are not clearly and closely related to the host instrument, and represent a single compound derivative that is required to be re-measured at fair value on a quarterly basis. In March 2019, the Term Loan Agreement was amended to reduce the 2019 minimum revenue target to $9.0 million and eliminate the 2018 revenue target. In September 2019, the Term Loan Agreement was amended to extend the interest-only payment period through December 31, 2021, to extend the initial principal repayment to March 31, 2022, and to reduce the minimum revenue targets to $4.0 million for the one-year period ended December 31, 2019, and $15.0 million and $43.0 million for the two-year periods ended December 31, 2020 and 2021, respectively. The fair value of the derivative at December 31, 2019 and 2018 is $2.4 million and $2.1 million, respectively. The estimated fair value of the derivative, at both dates, was determined using a probability-weighted discounted cash flow model that includes contingent interest payments under the following scenarios: 4% contingent interest beginning in 2020 (70%) and 4% contingent interest beginning in 2021 (30%). Should the Company’s assessment of these probabilities change, including amendments of certain revenue targets, there could be a change to the fair value of the derivative liability. The following table provides a roll-forward of the fair value of the derivative liability (in thousands): Balance at December 31, 2018 $ 2,142 Change in fair value of derivative liability, recorded as interest expense 283 Balance at December 31, 2019 $ 2,425

Restricted Cash

Restricted Cash	12 Months Ended
	Dec. 31, 2019
Restricted Cash [Abstract]
Restricted Cash	4. Restricted Cash The Company is required to maintain a security deposit for its operating lease agreement for the duration of the lease agreement and for its credit cards as long as they are in place. At December 31, 2019 and 2018, the Company had certificates of deposit for $180,000, which represented collateral as security deposits for its operating lease agreement for its facility and its credit cards .

Supplemental Balance Sheet Info

Supplemental Balance Sheet Information	12 Months Ended
	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Supplemental Balance Sheet Information	5. Supplemental Balance Sheet Information Property and Equipment Property and equipment consists of the following (in thousands) Estimated Useful December 31, December 31, Life (Years) 2019 2018 Office and computer equipment 3 $ 538 $ 409 Software 3 762 751 Laboratory equipment 5 4,747 4,636 Furniture 5-7 194 200 Manufacturing equipment 5 672 695 Manufacturing tooling and molds 0.5 255 255 T2-owned instruments and components 5 6,775 6,796 Leasehold improvements Lesser of useful life or remaining lease term 3,497 3,437 Construction in progress n/a 1,641 1,443 19,081 18,622 Less accumulated depreciation and amortization (13,236 ) (11,307 ) Property and equipment, net $ 5,845 $ 7,315 Construction in progress is primarily comprised of equipment that has not been placed in service. T2-owned instruments and components is comprised of raw materials and work-in-process inventory that are expected to be used or used to produce T2-owned instruments, based on the Company’s business model and forecast, and completed instruments that will be used for internal research and development, clinical studies or reagent rental agreements with customers. At December 31, 2019, there were $0.6 million of raw materials and work-in-process inventory in T2-owned instruments and components compared to $0.3 million at December 31, 2018. Completed T2-owned instruments are placed in service once installation procedures are completed and are depreciated over five years. Depreciation expense for T2-owned instruments placed at customer sites pursuant to reagent rental agreements is recorded as a component of cost of product revenue and totaled $0.8 million and $1.0 million for the year ended December 31, 2019 and 2018, respectively. Depreciation expense for T2-owned instruments used for internal research and development and clinical studies is recorded as a component of research and development expense. Depreciation and amortization expense of $2.2 million, $2.4 million and $2.9 million was charged to operations for the years ended December 31, 2019, 2018 and 2017, respectively. There were no property and equipment under finance leases included within property and equipment as of December 31, 2019, as the Company repurchased the equipment for $0.3 million in accordance with the terms of the Credit Facility (Note 6). Total property and equipment, gross, included $3.6 million for property and equipment recorded under capital leases as of December 31, 2018. Accumulated depreciation and amortization included $2.6 million for property and equipment recorded under capital leases as of December 31, 2018. During the fourth quarter of 2017, the Company received communication from the FDA that suggested the approval timeline for T2Bacteria would be longer than the Company initially anticipated. The Company assessed the recoverability of T2-owned instruments based on delayed T2Bacteria cash flows and recorded an impairment charge of $2.6 million, related to T2-owned instruments and components. The fair value used in the impairment calculation was based on the best estimated selling price of the underlying T2-owned instruments, less the estimated cost to sell the instruments. During the year-ended December 31, 2018, the Company recorded a $0.7 million impairment charge, in the cost of product revenue. The impairment charge related to manufacturing equipment for the Candida 1.0 cartridge, which was replaced by the Candida 1.1 cartridge, and version 1.0 T2-owned instruments, which will not be utilized by the Company going forward. Accrued Expenses Accrued expenses consist of the following (in thousands): December 31, December 31, 2019 2018 Accrued payroll and compensation $ 3,193 $ 2,940 Accrued final fee 2,445 1,375 Accrued research and development expenses 267 359 Accrued professional services 511 576 Accrued interest 908 — Operating lease liabilities 1,983 — Other accrued expenses 1,900 823 Total accrued expenses and other current liabilities $ 11,207 $ 6,073 At December 31, 2019 and December 31, 2018, the Company classified $2.4 million and $1.4 million, respectively, related to a fee associated with the Company’s Term Loan Agreement (Note 6), as accrued final fee in the table above to match the current classification of the associated debt. Included within other accrued expenses and accrued payroll and compensation in the table above, at December 31, 2019, is $1.0 million and $0.2 million, respectively, from the Second Amendment to Employment Agreement with John McDonough (the “Transition Agreement”) (Note 13).

Notes Payable

Notes Payable	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Notes Payable	6. Notes Payable Future principal payments on the notes payable as of December 31, 2019 are as follows (in thousands): Year ended December 31, 2020 $ — 2021 — 2022 48,077 2023 — 2024 — Total before unamortized discount and issuance costs 48,077 Less: paid-in-kind interest (3,284 ) Less: unamortized discount and issuance costs (1,891 ) Total notes payable $ 42,902 The Term Loan Agreement with CRG is classified as a current liability on the balance sheet at December 31, 2019 and 2018, based on the Company’s consideration of the probability of violating a minimum liquidity covenant included in the Term Loan Agreement. The Term Loan Agreement includes a subjective acceleration clause whereby an event of default, including a material adverse change in the business, operations, or conditions (financial or otherwise), could result in the acceleration of the obligations under the Term Loan Agreement. Term Loan Agreement In December 2016, the Company entered into a Term Loan Agreement (the “Term Loan Agreement”) with CRG. The Company borrowed $40.0 million pursuant to the Term Loan Agreement, which has a six-year term with three years (through December 30, 2019) of interest-only payments, which period was extended to four years (through December 30, 2020) upon achieving the Approval Milestone, after which quarterly principal and interest payments would be due through the December 30, 2022 maturity date. Interest on the amounts borrowed under the Term Loan Agreement accrues at an annual fixed rate of (a) prior to the Approval Milestone, 12.50%, 4.0% of which may be deferred during the interest-only period by adding such amount to the aggregate principal loan amount and (b) following the Approval Milestone, 11.50%, 3.5% of which may be deferred during the interest-only period by adding such amount to the aggregate principal loan amount. In addition, if the Company achieves certain financial performance metrics, the loan will convert to interest-only until the December 30, 2022 maturity, at which time all unpaid principal and accrued unpaid interest will be due and payable. The Company is required to pay a financing fee based on the loan principal amount drawn. The Company is also required to pay a final payment fee of 8% of the principal outstanding upon repayment. The Company is accruing the final payment fee as interest expense and it is included as a current liability at December 31, 2019 and 2018 on the balance sheet. The Company may prepay all or a portion of the outstanding principal and accrued unpaid interest under the Term Loan Agreement at any time upon prior notice subject to a certain prepayment fee during the first five years of the term and no prepayment fee thereafter. As security for its obligations under the Term Loan Agreement the Company entered into a security agreement with CRG whereby the Company granted a lien on substantially all of its assets, including intellectual property. The Term Loan Agreement also contains customary affirmative and negative covenants for a credit facility of this size and type, including a requirement to maintain a minimum cash balance. The Term Loan Agreement also requires the Company to achieve certain revenue targets, whereby the Company is required to pay double the amount of any shortfall as an acceleration of principal payments. In March 2019, the Term Loan Agreement was amended to reduce the 2019 minimum revenue target to $9.0 million and eliminate the 2018 revenue covenant. In exchange for the amendment, the Company agreed to reset the strike price of the warrants to purchase 528,958 shares of the Company’s common stock, issued in connection with the Term Loan Agreement, from $8.06 per share to $4.35 per share. In September 2019, the Term Loan Agreement was amended to extend the interest-only payment period through December 31, 2021, to extend the initial principal repayment to March 31, 2022, and to reduce the minimum product revenue target for 2019 from $9 million to $4 million, for the twenty-four month period beginning on January 1, 2019 from $95 million to $15 million and for the twenty-four month period beginning on January 1, 2020 from $140 million to $43 million. The Term Loan Agreement includes a subjective acceleration clause whereby an event of default, including a material adverse change in the business, operations, or conditions (financial or otherwise), could result in the acceleration of the obligations under the Term Loan Agreement. Under certain circumstances, a default interest rate of an additional 4.0% per annum will apply at the election of CRG on all outstanding obligations during the occurrence and continuance of an event of default. CRG has not exercised its right under this clause. The Company assessed the terms and features of the Term Loan Agreement, including the interest-only period dependent on the achievement of the Approval Milestone and the acceleration of the obligations under the Term Loan Agreement under an event of default, of the Term Loan Agreement in order to identify any potential embedded features that would require bifurcation. In addition, under certain circumstances, a default interest rate of an additional 4.0% per annum will apply at the election of CRG on all outstanding obligations during the occurrence and continuance of an event of default, The Company concluded that the features of the Term Loan Agreement are not clearly and closely related to the host instrument, and represent a single compound derivative that is required to be re-measured at fair value on a quarterly basis. The fair value of the derivative at December 31, 2019 and 2018 is $2.4 million and $2.1 million respectively. The Company classified the derivative liability as a current liability on the balance sheet at December 31, 2019 and 2018 to match the classification of the related Term Loan Agreement. Equipment Lease Credit Facility In October 2015, the Company signed the $10.0 million Credit Facility (the “Credit Facility”) with Essex Capital Corporation (“Essex”) to fund capital equipment needs. As one of the conditions of the Term Loan Agreement, the Credit Facility is capped at a maximum of $5.0 million. Under the Credit Facility, Essex will fund capital equipment purchases presented by the Company. The Company will repay the amounts borrowed in 36 equal monthly installments from the date of the amount funded. At the end of the 36 month lease term, the Company has the option to (a) repurchase the leased equipment at the lesser of fair market value or 10% of the original equipment value, (b) extend the applicable lease for a specified period of time, which will not be less than one year, or (c) return the leased equipment to the Lessor. In April 2016 and June 2016, the Company completed the first two draws under the Credit Facility of $2.1 million and $2.5 million, respectively. The Company made monthly payments of $67,000 under the first draw and $79,000 under the second draw. The borrowings under the Credit Facility were treated as capital leases and were included in property and equipment on the balance sheet. The amortization of the assets conveyed under the Credit Facility was included as a component of depreciation expense. During the year ended December 31, 2019, the Company repurchased the equipment for $0.3 million in accordance with the terms of the Credit Facility.

Stockholders' (Deficit) Equity

Stockholders' (Deficit) Equity	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Stockholders' (Deficit) Equity	7. Stockholders’ (Deficit) Equity Common Stock Each share of common stock is entitled to one vote. The holders of common stock are also entitled to receive dividends whenever funds are legally available and when declared by the Board of Directors, subject to the prior rights of holders of all classes of stock outstanding. The Company authorized 200,000,000 shares of common stock, $0.001 par value per share, of which 50,651,535 and 44,175,441 were outstanding as of December 31, 2019 and 2018, respectively. As of December 31, 2019, a total of 6,353,330 shares, 1,397,186 shares, and 1,097,249 shares of common stock were reserved for issuance upon (i) the exercise of outstanding stock options, (ii) the issuance of stock awards, and (iii) the exercise of warrants, respectively, under the Company’s 2014 Incentive Award Plan, Inducement Award Plan, and 2014 Employee Stock Purchase Plan. Equity Distribution Agreement On July 30, 2019, the Company entered into the Sales Agreement with Canaccord, as agent, pursuant to which the Company may offer and sell shares of common stock, for aggregate gross sale proceeds of up to $30.0 million from time to time through Canaccord. Upon delivery of a placement notice based on the Company’s instructions and subject to the terms and conditions of the Sales Agreement, Canaccord may sell the shares by methods deemed to be an “at the market” offering, in negotiated transactions at market prices prevailing at the time of sale or at prices related to such prevailing market prices, or by any other method permitted by law, including negotiated transactions, subject to the prior written consent of the Company. The Company is not obligated to make any sales of shares under the Sales Agreement. The Company or Canaccord may suspend or terminate the offering of shares upon notice to the other party, subject to certain conditions. Canaccord will act as sales agent on a commercially reasonable efforts basis consistent with its normal trading and sales practices and applicable state and federal law, rules and regulations and the rules of Nasdaq. The Company has agreed to pay Canaccord for its services of acting as agent 3% of the gross proceeds from the sale of the shares pursuant to the Sales Agreement. The Company has also agreed to provide Canaccord with customary indemnification for certain liabilities. Legal and accounting fees associated with the Sales Agreement were immaterial. Legal and accounting fees are expected to be changed to share capital upon issuance of shares under the Sales Agreement. During the year ended December 31, 2019, the Company sold 5,486,500 shares for net proceeds of $6.7 million after expenses in connection with the Sales Agreement. Purchase Agreement On July 29, 2019, the Company entered into a $30.0 million Purchase Agreement with Lincoln Park, pursuant to which the Company may sell and issue to Lincoln Park, and Lincoln Park is obligated to purchase, up to $30.0 million in value of its shares of common stock from time to time over a 36-month period starting from the effective date of the respective registration statement. The Company may direct Lincoln Park, at its sole discretion, and subject to certain conditions, to purchase up to 200,000 shares of common stock on any business day, provided that at least one business day has passed since the most recent purchase. The amount of a purchase may be increased under certain circumstances provided, however, that Lincoln Park’s committed obligation under any single purchase shall not exceed $2.0 million. The purchase price of shares of common stock related to the future funding will be based on the then prevailing market prices of such shares at the time of sales as described in the Purchase Agreement. The Purchase Agreement may not be readily available for use should the stock price fall under $1.00. In consideration for the execution and delivery of the Purchase Agreement, the Company issued 413,349 shares of common stock to Lincoln Park. Public Offering On September 15, 2017, the Company sold 5,031,250 shares of its common stock in a public offering at $4.00 per share, for an aggregate gross cash purchase price of $20.1 million, resulting in net proceeds of $18.8 million after underwriters discount and expenses. On June 4, 2018, the Company sold 7,015,000 shares of its common stock in a public offering at $7.50 per share, for an aggregate gross cash purchase price of $52.6 million, resulting in net proceeds of $49.2 million after underwriters discount and expenses.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	8. Stock-Based Compensation Stock Incentive Plans 2006 Stock Incentive Plan The Company’s 2006 Stock Option Plan (the “2006 Plan”) was established for granting stock incentive awards to directors, officers, employees and consultants to the Company. Upon closing of the Company’s Initial Public Offering (“IPO”) in August 2014, the Company ceased granting stock incentive awards under the 2006 Plan. The 2006 Plan provided for the grant of incentive and non-qualified stock options and restricted stock grants as determined by the Board of Directors. Under the 2006 Plan, stock options were generally granted with exercise prices equal to or greater than the fair value of the common stock as determined by the Board of Directors, expired no later than 10 years from the date of grant, and vest over various periods not exceeding 4 years. 2014 Stock Incentive Plan The Company’s 2014 Plan (the “2014 Plan” and, together with the 2006 Plan, the “Stock Incentive Plans”) provides for the issuance of shares of common stock in the form of stock options, awards of restricted stock, awards of restricted stock unit awards, performance awards, dividend equivalent awards, stock payment awards and stock appreciation rights to directors, officers, employees and consultants of the Company. Since the establishment of the 2014 Plan, the Company has only granted stock options and restricted stock units. Generally, stock options are granted with exercise prices equal to or greater than the fair value of the common stock on the date of grant, expire no later than 10 years from the date of grant, and vest over various periods not exceeding 4 years. The number of shares reserved for future issuance under the 2014 Plan is the sum of (1) 823,529, (2) any shares that were granted under the 2006 Plan which are forfeited, lapse unexercised or are settled in cash subsequent to the effective date of the 2014 Plan and (3) an annual increase on the first day of each calendar year beginning January 1, 2015 and ending on January 1, 2024, equal to the lesser of (A) 4% of the shares outstanding on the final day of the immediately preceding calendar year and (B) such smaller number of shares determined by the Board of Directors. As of December 31, 2019, there were 537,754 shares available for future grant under the Stock Incentive Plans. Inducement Award Plan The Company’s Amended and Restated Inducement Award Plan (“Inducement Plan”), which was adopted in March 2018 and amended and restated in February 2019, provides for the granting of equity awards to new employees, which includes options, restricted stock awards, restricted stock units, performance awards, dividend equivalent awards, stock payment awards and stock appreciation rights. The aggregate number of shares of common stock which may be issued or transferred pursuant to awards under the Inducement Plan is 1,625,000 shares. Any awards that forfeit, expire, lapse, or are settled for cash without the delivery of shares to the holder are available for the grant of an award under the Inducement Plan. Any shares repurchased by or surrendered to the Company that are returned shall be available for grant of an award under the Inducement Plan. The payment of dividend equivalents in cash in conjunction with any outstanding award shall not be counted against the shares available for issuance under the Inducement Plan. As of December 31, 2019, there were 717,000 shares available for future grant under the Inducement Plan. Pursuant to a January 2020 amendment, the aggregate number of shares of common stock which may be issued or transferred pursuant to awards under the Inducement Plan increased by 4,000,000 shares to 5,625,000 shares as of January 8, 2020. Stock Options During the years ended December 31, 2019, 2018, and 2017, the Company granted options with an aggregate fair value of $3.9 million, $5.8 million, and $2.7 million, respectively, which are being amortized into compensation expense over the vesting period of the options as the services are being provided. The following is a summary of option activity under the Stock Incentive Plans and Inducement Plan (in thousands, except share and per share amounts): Weighted-Average Weighted-Average Remaining Number of Exercise Price Per Contractual Term Aggregate Intrinsic Shares Share (In years) Value Outstanding at December 31, 2018 4,241,833 $ 6.98 7.02 $ 471 Granted 2,747,700 2.11 Exercised (2,119 ) 2.01 1 Forfeited (426,960 ) 5.06 Canceled (207,124 ) 8.62 Outstanding at December 31, 2019 6,353,330 4.95 7.29 229 Exercisable at December 31, 2019 3,242,751 6.84 5.55 33 Vested or expected to vest at December 31, 2019 5,751,313 $ 5.16 7.09 $ 199 The total intrinsic value of options exercised in the year ended December 31, 2019 was immaterial. The total intrinsic value of options exercised in the years ended December 31, 2018 and 2017 were $1.4 million and $0.6 million, respectively. The weighted‑average fair values of options granted in the years ended December 31, 2019, 2018, and 2017 were $1.41, $3.54, and $2.95 per share, respectively, and were calculated using the following estimated assumptions: Year ended December 31, 2019 2018 2017 Weighted-average risk-free interest rate 1.97 % 2.67 % 1.99 % Expected dividend yield 0.00 % 0.00 % 0.00 % Expected volatility 78 % 68 % 60 % Expected terms 6.0 years 6.0 years 6.0 years The total fair values of stock options that vested during the years ended December 31, 2019, 2018, and 2017 were $3.1 million, $3.0 million, and $3.5 million, respectively. As of December 31, 2019, there was $5.8 million of total unrecognized compensation cost related to non‑vested stock options granted under the Stock Incentive Plans. Total unrecognized compensation cost will be adjusted for future changes in the estimated forfeiture rate. The Company expects to recognize that cost over a remaining weighted‑average period of 2.6 years as of December 31, 2019. Restricted Stock Units During the year ended December 31, 2019, the Company awarded shares of restricted stock units to certain employees at no cost to them, which cannot be sold, assigned, transferred or pledged during the restriction period. The restricted stock units vest through the passage of time, assuming continued employment. Restricted stock units are not included in issued and outstanding common stock until the shares are vested and released. During the year ended December 31, 2018, 78,172 restricted stock units vested but were not reflected as outstanding shares due to a deferred release date. Included in the nonvested restricted stock units at December 31, 2019 are 755,168 restricted stock units with market conditions, which were granted in the year ended December 31, 2018 and vest upon the achievement of stock price targets. The compensation cost for restricted stock units with market conditions is being recorded over the derived service period and was $1.0 million and $4.5 million and for the years ended December 31, 2019 and 2018, respectively. The following is a summary of restricted stock unit activity under the 2014 Plan (in thousands, except share and per share amounts): Weighted-Average Number of Grant Date Fair Shares Value Nonvested at December 31, 2018 1,198,634 $ 5.04 Granted 589,142 3.23 Vested (189,129 ) 6.41 Forfeited (303,139 ) 4.33 Canceled — — Nonvested at December 31, 2019 1,295,508 $ 4.19 As of December 31, 2019, there was $1.3 million of total unrecognized compensation cost related to non‑vested restricted stock units granted under the 2014 Plan. Total unrecognized compensation cost will be adjusted for future changes in the estimated forfeiture rate. The Company expects to recognize that cost over a remaining weighted‑average period of 2.0 years as of December 31, 2019. Employee Stock Purchase Plan The 2014 Employee Stock Purchase Plan (the “2014 ESPP”) period is semi-annual and allows participants to purchase the Company’s common stock at 85% of the lower of (i) the market value per share of common stock on the first day of the offering period or (ii) the market value per share of the common stock on the purchase date. Each participant can purchase up to a maximum of $25,000 per calendar year in fair market value. The first plan period began on August 7, 2014. Stock-based compensation expense from the 2014 ESPP for the years ended December 31, 2019, 2018 and 2017 was approximately $0.4 million, $0.4 million and $0.2 million, respectively. During the years ended December 31, 2019, 306,824 shares were purchased through the 2014 ESPP. The fair value of the purchase rights granted under this plan was estimated on the date of grant and uses the following weighted-average assumptions, which were derived in a manner similar to those discussed in Note 2 relative to stock options: Year ended December 31, 2019 2018 2017 Weighted-average risk-free interest rate 2.44 % 2.24 % 1.03 % Expected dividend yield 0.00 % 0.00 % 0.00 % Expected volatility 71 % 70 % 68 % Expected terms 0.5 years 0.5 years 0.5 years The 2014 ESPP provides initially for the granting of up to 220,588 shares of the Company’s common stock to eligible employees. In addition, on the first day of each calendar year beginning January 1, 2015 and ending on January 1, 2024, the number of common shares available under the 2014 ESPP shall be increased by the number of shares equal to the lesser of (1) 220,588 shares, (2) 1% of the common shares outstanding on the final day of the immediately preceding calendar year and (3) such smaller number of common shares as determined by the Board of Directors. At December 31, 2019, there were 142,432 shares available under the 2014 ESPP. Stock‑Based Compensation Expense The following table summarizes the stock-based compensation expense resulting from awards granted under Stock Incentive Plans, the Inducement Plan and 2014 ESPP, that was recorded in the Company’s results of operations for the years presented (in thousands): Year ended December 31, 2019 2018 2017 Cost of product revenue $ 365 $ 803 $ 125 Research and development 1,184 1,603 1,384 Selling, general and administrative 3,888 7,362 3,196 Total stock-based compensation expense $ 5,437 $ 9,768 $ 4,705 For the year ended December 31, 2019, stock-based compensation expense capitalized as part of inventory or T2-owned instruments and components was immaterial. For the years ended December 31, 2018 and 2017, $0.1 million of stock-based compensation expense was capitalized as part of inventory or T2-owned instruments and components.

Warrants

Warrants	12 Months Ended
	Dec. 31, 2019
Warrants And Rights Note Disclosure [Abstract]
Warrants	9. Warrants In connection with the Term Loan Agreement entered into in December 2016, the Company issued to CRG warrants to purchase a total of 528,958 shares of the Company’s common stock. The warrants are exercisable any time prior to December 30, 2026 at a price of $4.35 per share, which was amended in March 2019 from an original price of $8.06 per share, with typical provisions for termination upon a change of control or a sale of all or substantially all of the assets of the Company. In connection with the September 2019 amendment of the Term Loan Agreement, the Company issued to CRG warrants to purchase 568,291 shares of the Company’s common stock (“New Warrants”) at an exercise price of $1.55, with typical provisions for termination upon a change of control or a sale of all or substantially all of the assets of the Company. The Company also reduced the exercise price for the warrants previously issued to CRG to $1.55. All of the New Warrants are exercisable any time prior to September 9, 2029. The warrants are classified within shareholders’ equity, and the proceeds were allocated between the debt and warrants based on their relative fair value. The fair value of the new and amended warrants was determined by the Black-Scholes-Merton option pricing model. The incremental fair value of the amended warrants of $0.1 million and the fair value of the New Warrants of $0.7 million were recorded as debt discount and additional paid-in-capital.

Net Loss Per Share

Net Loss Per Share	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Net Loss Per Share	10. Net Loss Per Share The following table presents the calculation of basic and diluted net loss per share applicable to common stockholders (in thousands, except share and per share data): Year ended December 31, 2019 2018 2017 Numerator: Net loss $ (59,006 ) $ (51,153 ) $ (62,428 ) Denominator: Weighted-average number of common shares outstanding — basic and diluted 45,507,754 40,558,826 32,131,512 Net loss per share applicable to common stockholders — basic and diluted $ (1.30 ) $ (1.26 ) $ (1.94 ) The following shares were excluded from the calculation of diluted net loss per share applicable to common stockholders, prior to the application of the treasury stock method, because their effect would have been anti ‑ Year ended December 31, 2019 2018 2017 Options to purchase common shares 6,353,330 4,241,833 3,785,083 Restricted stock units 1,295,508 1,198,634 606,497 Warrants to purchase common stock 1,097,249 528,958 528,958 Total 8,746,087 5,969,425 4,920,538

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes The reconciliation of the U.S. federal statutory rate to the Company’s effective tax rate is as follows: Year Ended December 31, 2019 2018 2017 Tax at statutory rates 21.0 % 21.0 % 35.0 % State income taxes 2.6 3.6 6.5 Permanent differences (1.2 ) (0.6 ) (2.5 ) Research and development credits 1.0 1.0 1.5 US tax rate change — - (52.7 ) Change in valuation allowance (23.4 ) (25.0 ) 12.2 Effective tax rate 0.0 % 0.0 % 0.0 % The significant components of the Company’s deferred tax asset consist of the following at December 31, 2019 and 2018 (in thousands): December 31, 2019 2018 Deferred tax assets: Net operating loss carryforwards $ 86,990 $ 73,612 Tax credits 8,329 7,603 Other temporary differences 2,888 3,156 Start-up expenditures 2,716 3,026 Stock option expenses 3,450 3,130 Lease liability 987 — Total deferred tax assets 105,360 90,527 Deferred tax asset valuation allowance (104,204 ) (90,361 ) Net deferred tax assets 1,156 166 Deferred tax liabilities: Right of use asset (859 ) — Prepaid expenses (297 ) (166 ) Net deferred taxes $ — $ — In 2019 and 2018, the Company did not record a benefit for income taxes related to its operating losses incurred. ASC 740 requires a valuation allowance to reduce the deferred tax assets reported if, based on the weight of available evidence, it is more likely than not that some portion or all of the deferred tax assets will not be realized. Based upon the level of historical U.S. losses and future projections over the period in which the net deferred tax assets are deductible, at this time, management believes it is more likely than not that the Company will not realize the benefits of these deductible differences, and as a result the Company continues to maintain a valuation allowance for the full amount of the 2019 deferred tax assets. The valuation allowance increased by $13.8 million and increased $12.8 million for the years ended December 31, 2019 and 2018, respectively. The increase in the 2019 valuation allowance is primarily attributable to the current year loss. The increase in 2018 was primarily attributable to the loss incurred for the year. As of December 31, 2019, the Company had federal and state net operating losses of $329.6 million and $292.4 million, respectively, which are available to offset future taxable income, if any, of which $228.2 million of federal and $288.0 million of state carry forwards will expire in varying amounts through 2037 and 2039, respectively. Additionally, $101.4 million of federal net operating loss carry forwards and $4.4 million of state net operating loss carryforwards will carryforward indefinitely, subject to annual taxable income limitations in the year of utilization. The Company also had federal and state research and development tax credits of $5.5 million and $3.6 million, respectively, which expire at various dates through 2039 for federal purposes and 2034 for state purposes. Under the provisions of the Internal Revenue Code, the net operating loss and tax credit carryforwards are subject to review and possible adjustment by the Internal Revenue Service and state tax authorities. Net operating loss and tax credit carryforwards may become subject to an annual limitation in the event of certain cumulative changes in the ownership interest of significant stockholders over a three-year period in excess of 50%, as defined under Sections 382 and 383 of the Internal Revenue Code, respectively, as well as similar state provisions. This could limit the amount of tax attributes that can be utilized annually to offset future taxable income or tax liabilities. The amount of the annual limitation is determined based on the value of the Company immediately prior to the ownership change. Subsequent ownership changes may further affect the limitation in future years. The Company has completed several financings since its inception which may have resulted in a change in control as defined by Sections 382 and 383 of the Internal Revenue Code, or could result in a change in control in the future. The Company has not conducted an assessment to determine whether there may have been a Section 382 or 383 ownership change. The Company has no unrecognized tax benefits. Interest and penalty charges, if any, related to uncertain tax positions would be classified as income tax expenses in the accompanying consolidated statements of operations. At December 31, 2019 and 2018, the Company had no accrued interest or penalties related to uncertain tax positions. The Company files income tax returns in the U.S. federal tax jurisdiction and various state jurisdictions. Since the Company is in a loss carryforward position, the Company is generally subject to examination by the U.S. federal, state and local income tax authorities for all tax years in which a loss carryforward is available. The Company does not have any international operations as of December 31, 2019. The statute of limitations for assessment by federal and state tax jurisdictions in which the Company has business operations is open for tax years ending December 31, 2016 and after. The tax years under examination vary by jurisdiction.

Leases

Leases	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	12. Leases Operating Leases The Company leases certain office space, laboratory space, and equipment. At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present. The Company does not recognize right-of-use assets or lease liabilities for leases determined to have a term of 12 months or less. For new and amended leases beginning in 2019 and after, the Company has elected to account for the lease and non-lease components as a combined lease component. In August 2010, the Company entered into an operating lease for office and laboratory space at its headquarters in Lexington, Massachusetts. The lease commenced in January 2011, with the Company providing a security deposit of $400,000. In accordance with the operating lease agreement, the Company reduced its security deposit to $180,000 in January 2018, which is recorded as restricted cash in the consolidated balance sheets. In March 2017, the Company entered into an amendment to extend the term to December 2021. In May 2013, the Company entered into an operating lease for additional office, laboratory and manufacturing space in Wilmington, Massachusetts. In August 2018, the Company entered into an amendment to extend the term to December 2020. In November 2014, the Company entered into an agreement to rent additional office space in Lexington, Massachusetts. In April 2015, the Company entered into an amendment to extend the term to December 31, 2017. In connection with this agreement, the Company paid a security deposit of $50,000, which is recorded as a component of other assets in the consolidated balance sheets. In May 2015, the Company entered into an amendment to expand existing manufacturing facilities in Lexington, Massachusetts. In September 2017, the Company entered into an amendment to extend the term to December 31, 2021. In November 2014, the Company entered into a lease for additional laboratory space in Lexington, Massachusetts. The lease term commenced in April 2015 and extended for six years. The rent expense, inclusive of the escalating rent payments, is recognized on a straight-line basis over the lease term. As an incentive to enter into the lease, the landlord paid approximately $1.4 million of the $2.2 million space build-out costs. Prior to the adoption of ASC 842, the incentive was recorded as a component of lease incentives on the consolidated balance sheets and was amortized as a reduction in rent expense on a straight-line basis over the term of the lease. Upon adoption of the new standard the unamortized balance of the lease incentive as of January 1, 2019 was reclassified as a reduction to the initial recognition of the right-of-use asset related to this lease. In connection with this lease agreement, the Company paid a security deposit of $281,000, which is recorded as a component of both prepaid expenses and other current assets and other assets in the consolidated balance sheets. Operating leases are amortized over the lease term and included in costs and expenses in the consolidated statement of operations and comprehensive loss. Variable lease costs are recognized in costs and expenses in the consolidated statement of operations and comprehensive loss as incurred. Finance Leases In October 2015, the Company signed a $10.0 million Credit Facility (the “Credit Facility”) to fund capital equipment needs. As one of the conditions of the Term Loan Agreement, the Credit Facility is capped at a maximum of $5.0 million. Under the Credit Facility, the lender will fund capital equipment purchases presented by the Company. The Company will repay the amounts borrowed in 36 equal monthly installments from the date of the amount funded. At the end of the 36 month lease term, the Company has the option to (a) repurchase the leased equipment at the lesser of fair market value or 10% of the original equipment value, (b) extend the applicable lease for a specified period of time, which will not be less than one year, or (c) return the leased equipment to the lessor. In April 2016 and June 2016, the Company completed the first two draws under the Credit Facility of $2.1 million and $2.5 million, respectively. The Company made monthly payments of $67,000 under the first draw and $79,000 under the second draw. The property and equipment from the borrowings under the Credit Facility are treated as finance leases and are included in property and equipment on the balance sheet. The amortization of the assets conveyed under the Credit Facility is included as a component of depreciation expense. During the year ended December 31, 2019, the Company repurchased the equipment for $0.3 million in accordance with the terms of the Credit Facility. The following table summarizes the effect of operating and finance lease costs in the Company’s consolidated statement of operations and comprehensive loss (in thousands): Lease cost Year ended December 31, 2019 Finance lease cost: Amortization of right-of-use assets $ 235 Interest on lease liabilities 36 Operating lease cost 1,995 Variable lease cost 659 Total lease cost $ 2,925 The following table summarizes supplemental information for the Company’s finance and operating leases: Other information Year ended December 31, 2019 Weighted-average remaining lease term - operating leases (in years) 1.9 years Weighted-average discount rate - operating leases 11.9 % The minimum lease payments for the next five years and thereafter is expected to be as follows (in thousands): December 31, 2019 Maturity of lease liabilities Operating Leases 2020 $ 2,314 2021 1,951 2022 23 2023 — 2024 — Thereafter — Total lease payments $ 4,288 Less: effect of discounting (432 ) Present value of lease liabilities $ 3,856 The following table summarizes the presentation of the Company’s operating leases in its consolidated balance sheets (in thousands): Leases Classification December 31, 2019 Assets Operating lease assets Operating lease assets 3,360 Total lease assets $ 3,360 Liabilities Current Operating Accrued expenses and other current liabilities $ 1,983 Noncurrent Operating Noncurrent operating lease liabilities 1,873 Total lease liabilities $ 3,856 Under ASC 840, future minimum non-cancelable lease payments under the Company’s operating leases as of December 31, 2018 were as follows (in thousands): Year ending December 31, 2019 $ 2,225 2020 2,277 2021 1,926 $ 6,428 Under ASC 840, rent expense for the years ended December 31, 2018, and 2017 was $2.0 million, and $1.9 million, respectively.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	13. Commitments and Contingencies Leases Refer to Note 12, Leases, for discussion of the commitments associated with the Company’s leases. License Agreement In 2006, the Company entered into a license agreement with a third party, pursuant to which the third party granted the Company an exclusive, worldwide, sublicenseable license under certain patent rights to make, use, import and commercialize products and processes for diagnostic, industrial and research and development purposes. The Company agreed to pay an annual license fee ranging from $5,000 to $25,000 for the royalty‑bearing license to certain patents. For the years ended December 31, 2019, 2018 and 2017, the Company incurred immaterial amounts for regulatory milestones, license fees and reimbursed patent costs under the agreement. The Company also issued a total of 84,678 shares of common stock pursuant to the agreement in 2006 and 2007, which were recorded at fair value at the date of issuance. The Company is required to pay royalties on net sales of products and processes that are covered by patent rights licensed under the agreement at a percentage ranging between 0.5% - 3.5%, subject to reductions and offsets in certain circumstances, as well as a royalty on net sales of products that the Company sublicenses at 10% of specified gross revenue. Royalties that became due under this agreement for the years ended December 31, 2019, 2018 and 2017 were immaterial. Transition Agreement On July 30, 2019, the Company announced that founding CEO John McDonough was named Executive Chairman of the Board until a successor is named at which time Mr. McDonough will become non-executive Chairman of the Board. John Sperzel was named CEO in January 2020. In connection with John McDonough’s transition to Non-Executive Chairman of the Board from CEO, the Company agreed to transition payments and health benefits of approximately $1.0 million, which will be paid over the 15 month period following Mr. Sperzel’s start date, and are recorded in other accrued expenses at December 31, 2019. Included within accrued payroll and compensation at December 31, 2019 is $0.2 million related to bonus.

401(k) Savings Plan

401(k) Savings Plan	12 Months Ended
	Dec. 31, 2019
Compensation And Retirement Disclosure [Abstract]
401(k) Savings Plan	14. 401(k) Savings Plan In March, 2008, the Company established a retirement savings plan under Section 401(k) of the Internal Revenue Code (the “401(k) Plan”). The 401(k) Plan covers substantially all employees of the Company who meet minimum age and service requirements and allows participants to defer a portion of their annual compensation on a pretax basis. Company contributions to the 401(k) Plan may be made at the discretion of the Board of Directors. Company contributions to the 401(k) Plan were $195,000, $126,000 and $190,000 for the years ended December 31, 2019, 2018 and 2017, respectively.

Co-Development Agreements

Co-Development Agreements	12 Months Ended
	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Co-Development Agreements	15. Co-Development Agreements Canon US Life Sciences On February 3, 2015, the Company entered into a Co-Development Partnership Agreement (the “Co-Development Agreement”) with Canon U.S. Life Sciences, Inc. (“Canon US Life Sciences”) to develop a diagnostic test panel to rapidly detect Lyme disease. On September 21, 2016, Canon became a related party when the Company sold the Canon Shares for an aggregate cash purchase price of $39.7 million, which represented 19.9% of the outstanding shares of common stock of the Company. Under the terms of the Co-Development Agreement, the Company received an upfront payment of $2.0 million from Canon US Life Sciences and the agreement includes an additional $6.5 million of consideration upon achieving certain development and regulatory milestones for total aggregate payments of up to $8.5 million. In October 2015, the Company achieved a specified technical requirement and received $1.5 million related to the achievement of the milestone. In May 2018, the Company achieved the next milestone and received $2.0 million. As of December 31, 2019, the Company had determined that it will not achieve the final regulatory milestone of $3.0 million prior to the termination of this agreement and therefore, as of December 31, 2019, all revenue related to the Co-Development Agreement has been recognized. All payments under the Co-Development Agreement are non-refundable once received. The Company will retain exclusive worldwide commercialization rights of any products developed under the Co-Development Agreement, including sales, marketing and distribution and Canon US Life Sciences will not receive any commercial right and will be entitled to only receive royalty payments on the sales of all products developed under the Co-Development Agreement. Either party may terminate the Co-Development Agreement upon the occurrence of a material breach by the other party (subject to a cure period). The Company evaluated the promised goods and services under the Co-Development Agreement and determined that the Co-Development Agreement included one The Company recorded revenue of $0.5 million, $1.5 million and $0.3 million for the years ended December 31, 2019, 2018, and 2017, respectively, under the Co-Development Agreement. Allergan Sales, LLC On November 1, 2016, the Company entered into a Co-Development, Collaboration and Co-Marketing Agreement (the “Allergan Agreement”) with Allergan Sales, LLC (“Allergan Sales”) to develop (1) a direct detection diagnostic test panel that adds one additional bacteria species to the existing T2Bacteria product candidate (the “T2Bacteria II Panel”), and (2) a direct detection diagnostic test panel for testing drug resistance directly in whole blood (the “T2GNR Panel” and, together with the T2Bacteria II Panel, the “Developed Products”). In addition, both the Company and Allergan Sales will participate in a joint research and development committee and Allergan Sales will receive the right to cooperatively market the T2Candida, T2Bacteria, and the Developed Products under the Allergan Agreement to certain agreed-upon customers. The Company achieved the final developmental milestone under the Allergan Agreement in October 2018. Under the terms of the Allergan Agreement, the Company received an upfront payment of $2.0 million from Allergan Sales and received additional milestone payments upon achieving certain developmental milestones for total aggregate payments of up to $4.0 million. All payments under the Allergan Agreement are non-refundable once received. The Company will retain exclusive worldwide commercialization rights of any products developed under the Allergan Agreement, including distribution, subject to Allergan Sales’ right to co-market the Developed Products. Allergan Sales, at its election, may co-market T2Candida, T2Bacteria and the Developed Products worldwide to certain agreed-upon customers and will receive royalty based on its sales for a period of time. The Company evaluated the promised goods and services under the Allergan Agreement and determined that the Allergan Agreement included two In October 2018, the Company achieved the final developmental milestone under the Allergan Agreement. The Company did not record any revenue for the year ended December 31, 2019 and recorded revenue of $3.1 million and $0.9 million during the years ended December 31, 2018 and 2017, respectively, under the Allergan Agreement. The adoption of ASC 606 on January 1, 2018 resulted in a $0.1 million adjustment to the opening accumulated deficit as of January 1, 2018 due to higher revenue recognition for the Allergan Agreement under ASC 606. CARB-X In March 2018, the Company was awarded a grant of up to $2.0 million from CARB-X. The collaboration with CARB-X will be used to accelerate the development of new tests to identify bacterial pathogens and resistance markers directly in whole blood more rapidly than is possible using today’s diagnostic tools. The new tests aim to expand the T2Dx instrument product line by detecting 20 additional bacterial species and resistance targets, with a focus on blood borne pathogens on the United States Centers for Disease Control and Prevention (“CDC”) antibiotic resistance threat list. Under this cost-sharing agreement, the Company may be reimbursed up to $1.1 million, with the possibility of up to an additional $0.9 million based on the achievement of certain project milestones. In January 2019, the Company was awarded the $0.9 million reimbursement option. The Company recorded revenue of $0.9 million and $1.1 million for the years ended December 31, 2019 and 2018 under the CARB-X Agreement, respectively. US Government Contract In September 2019, the Biomedical Advanced Research and Development Authority (“BARDA”) awarded the Company a milestone-based contract, with an initial value of $6.0 million, and a potential value of up to $69.0 million, if BARDA awards all contract options. BARDA operates within the Office of the Assistant Secretary for Preparedness and Response (“ASPR”) at the U.S. Department of Health and Human Services’ (“HHS”). If BARDA awards and the Company completes all options, the Company’s management believes it will enable a significant expansion of the Company’s current portfolio of diagnostics for sepsis-causing pathogen and antibiotic resistance genes. The Company recorded contribution revenue of $1.5 million for the year ended December 31, 2019 under the US Government Contract.

Quarterly Financial Data (unaud

Quarterly Financial Data (unaudited)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (unaudited)	16. Quarterly Financial Data (unaudited) Year ended December 31, 2019 (In thousands, except per share data) First Quarter Second Quarter Third Quarter Fourth Quarter Revenue: Product revenue $ 1,314 $ 1,274 $ 1,177 $ 1,562 Research revenue 142 71 56 294 Contribution revenue 329 459 444 1,213 Total revenue $ 1,785 $ 1,804 $ 1,677 $ 3,069 Costs and expenses: Cost of product revenue 4,388 4,820 3,944 3,611 Research and development 3,901 4,048 4,098 4,279 Selling, general and administrative 7,055 6,722 5,981 7,546 Total costs and expenses 15,344 15,590 14,023 15,436 Loss from operations $ (13,559 ) $ (13,786 ) $ (12,346 ) $ (12,367 ) Net loss $ (15,147 ) $ (15,647 ) $ (14,171 ) $ (14,041 ) Per share data: Net loss per common share—basic and diluted $ (0.34 ) $ (0.35 ) $ (0.31 ) $ (0.29 ) Year ended December 31, 2018 (In thousands, except per share data) First Quarter Second Quarter Third Quarter Fourth Quarter Revenue: Product revenue $ 1,048 $ 1,220 $ 1,218 $ 1,319 Research revenue 1,263 2,711 1,248 473 Total revenue $ 2,311 $ 3,931 $ 2,466 $ 1,792 Costs and expenses: Cost of product revenue 3,273 3,458 3,042 5,631 Research and development 4,718 3,749 2,725 3,297 Selling, general and administrative 5,755 7,611 5,873 6,458 Total costs and expenses 13,746 14,818 11,640 15,386 Loss from operations $ (11,435 ) $ (10,887 ) $ (9,174 ) $ (13,594 ) Net loss $ (12,913 ) $ (12,324 ) $ (10,767 ) $ (15,149 ) Per share data: Net loss per common share—basic and diluted $ (0.36 ) $ (0.32 ) $ (0.25 ) $ (0.34 )

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	17. Subsequent Events Equity Distribution Agreement On March 9, 2020, the Company entered into an amendment to the Sales Agreement with Canaccord to increase the aggregate gross sales amount from $30.0 million to $65.0 million. During the period from January 1, 2020 through March 13, 2020, the Company sold 49,401,624 shares for net proceeds of approximately $29.3 million after estimated expenses in connection with the Sales Agreement.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The Company’s financial statements have been prepared in conformity with accounting principles generally accepted 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 and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). The Company’s consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary, T2 Biosystems Securities Corporation. All intercompany balances and transactions have been eliminated.
Use of Estimates	Use of Estimates The preparation of the Company’s consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. The Company utilizes certain estimates in the determination of the accounts receivable allowance, the excess and obsolete inventory, the net realizable value of inventory, the fair value of its stock options, as well as restricted stock units that have market conditions, deferred tax valuation allowances, revenue recognition, expenses relating to research and development contracts, accrued expenses, the fair value of a derivative liability, the fair value of warrants and classification of the value of instrument raw material and work-in-process inventory between inventory and property and equipment. The Company bases its estimates on historical experience and other market ‑
Segment Information	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 ‑
Geographic Information	Geographic Information The Company sells its products domestically and internationally. International sales to a single country did not exceed 10% of total revenue in any year. Total international sales were approximately $2.8 million or 34% of total revenue in 2019, $2.2 million or 21% of total revenue in 2018 and $0.9 million or 19% of total revenue in 2017. As of December 31, 2019 and 2018, the Company had outstanding receivables of $1.2 million and $0.9 million, respectively, from customers located outside of the U.S.
Off Balance Sheet Risk and Concentrations of Risk	Off ‑ The Company has no significant off-balance sheet risks, such as foreign exchange contracts, option contracts, or other foreign hedging arrangements. Cash and cash equivalents are financial instruments that potentially subject the Company to concentrations of credit risk. At December 31, 2019 and 2018, substantially all of the Company’s cash was deposited in accounts at one financial institution, with a portion invested in money market funds that are invested in short-term U.S. government agency securities. The Company maintains its cash deposits, which at times may exceed the federally insured limits, with a large financial institution and, accordingly, the Company believes such funds are subject to minimal credit risk. For the year ended December 31, 2019, the Company derived approximately 19% of its total revenue from one customer, 11% of its total revenue from a second customer, and 8% of its total revenue from a third customer. For the year ended December 31, 2018, the Company derived approximately 29% of its total revenue from one customer, 15% of its total revenue from a second customer and 10% of its total revenue from a third customer. For the year ended December 31, 2017, the company derived 19% of its total revenue from one customer and 10% of its revenue from a second customer. At December 31, 2019, the Company had two customers that represented 27% and 10%, respectively, of its accounts receivable balance. At December 31, 2018, the Company had two customers that represented 25% and 22%, respectively, of its accounts receivable balance. The Company relies on single-source suppliers for some components and materials used in its products and product candidates. The Company has entered into supply agreements with most of its suppliers to help ensure component availability and flexible purchasing terms with respect to the purchase of such components. While the Company believes replacement suppliers exist for all components and materials obtained from single sources, establishing additional or replacement suppliers for any of these components or materials, if required, may not be accomplished quickly. Even if the Company is able to find a replacement supplier, the replacement supplier would need to be qualified and may require additional regulatory authority approval, which could result in further delay. If third-party suppliers fail to deliver the required commercial quantities of materials on a timely basis and at commercially reasonable prices, and the Company is unable to find one or more replacement suppliers capable of production at a substantially equivalent cost in substantially equivalent volumes and quality on a timely basis, the continued commercialization of products, the supply of products to customers and the development of any future products would be delayed, limited or prevented, which could have an adverse impact on the business.
Cash Equivalents	Cash Equivalents Cash equivalents include all highly liquid investments with original maturities of 90 days or less. Cash equivalents consist of money market funds invested in short-term U.S. government agency securities as of December 31, 2019 and 2018.
Accounts Receivable	Accounts Receivable The Company’s accounts receivable consists of amounts due from product sales to commercial customers and from research and development arrangements with partners. At each reporting period, management reviews all outstanding balances to determine if the facts and circumstances of each customer relationship indicate the need for a reserve. The Company does not require collateral and did not have an allowance for doubtful accounts at December 31, 2019 or 2018.
Inventories	Inventories Inventories are stated at the lower of cost or net realizable value. The Company determines the cost of its inventories, which includes amounts related to materials, direct labor, and manufacturing overhead, on a first-in, first-out basis. The Company performs an assessment of the recoverability of capitalized inventory during each reporting period, and writes down any excess and obsolete inventories to their realizable value in the period in which the impairment is first identified. Shipping and handling costs incurred for inventory purchases are capitalized and recorded upon sale in cost of product revenues in the consolidated statements of operations and comprehensive loss or are included in the value of T2-owned instruments and components, a component of property and equipment, net, and depreciated. The Company capitalizes inventories in preparation for sales of products when the related product candidates are considered to have a high likelihood of regulatory clearance, which for the T2Dx Instrument, T2Candida and T2Bacteria was upon the achievement of regulatory clearance, and the related costs are expected to be recoverable through sales of the inventories. In addition, the Company capitalizes inventories related to the manufacture of instruments that have a high likelihood of regulatory clearance, which for the T2Dx Instrument was upon the achievement of regulatory clearance, and will be retained as the Company’s assets, upon determination that the instrument has alternative future uses. In determining whether or not to capitalize such inventories, the Company evaluates, among other factors, information regarding the product candidate’s status of regulatory submissions and communications with regulatory authorities, the outlook for commercial sales and alternative future uses of the product candidate. Costs associated with development products prior to satisfying the inventory capitalization criteria are charged to research and development expense as incurred. The Company classifies instruments that are Company-owned, as a component of property and equipment. Raw material and work-in-process inventories that are expected to be used to produce Company-owned instruments, based on the Company’s business model and forecast, are also classified as property and equipment. Company-owned instruments are instruments that are manufactured and placed with customers in connection with reagent rental agreements, or are used for internal purposes. The components of inventory consist of the following (in thousands): December 31, December 31, 2019 2018 Raw materials $ 1,617 $ 639 Work-in-process 1,227 1,713 Finished goods 755 325 Total inventories, net $ 3,599 $ 2,677
Fair Value Measurements	Fair Value Measurements The Company is required to disclose information on all assets and liabilities reported at fair value that enables an assessment of the inputs used in determining the reported fair values. ASC 820, Fair Value Measurements and Disclosures Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability, and are developed based on the best information available in the circumstances. The fair value hierarchy applies only to the valuation inputs used in determining the reported fair value of the investments and is not a measure of the investment credit quality. The hierarchy defines three levels of valuation inputs: Level 1 — Quoted unadjusted prices for identical instruments in active markets. Level 2 — Quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model ‑ Level 3 — Model derived valuations in which one or more significant inputs or significant value drivers are unobservable, including assumptions developed by the Company. The fair value hierarchy prioritizes valuation inputs based on the observable nature of those inputs. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability (Note 3). For certain financial instruments, including accounts receivable, prepaid expenses and other current assets, accounts payable and accrued expenses, the carrying amounts approximate their fair values as of December 31, 2019 and 2018 because of their short-term nature. At December 31, 2019 and 2018, the fair value of the derivative liability was determined using Level 3 inputs using a valuation model that includes assumptions from the Company (Note 6).
Property and Equipment	Property and Equipment Property and equipment are recorded at cost and depreciated over their estimated useful lives using the straight‑line method. Property and equipment, net, includes assets under capital leases. Property and equipment includes raw materials and work-in-process inventory that are expected to be used or used to produce T2-owned instruments based on the Company’s business model and forecast, and finished instruments that will be used for internal research and development, clinical studies or reagent rental agreements with customers. Completed T2-owned instruments are placed in service once installation procedures are completed. Construction in progress is primarily comprised of equipment that has not been placed in service.
Leases	Leases The Company adopted Topic 842, Leases Leases At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present. Leases with a term greater than one year are recognized on the balance sheet as right-of-use assets, lease liabilities and long-term lease liabilities. The Company has elected not to recognize on the balance sheet leases with terms of one year or less. Operating lease liabilities and their corresponding right-of-use assets are recorded based on the present value of lease payments over the expected remaining lease term. However, certain adjustments to the right-of-use asset may be required for items such as prepaid or accrued lease payments. The interest rate implicit in lease contracts is typically not readily determinable. As a result, the Company utilizes its incremental borrowing rates, which are the rates incurred to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment. In accordance with the guidance in ASC 842, components of a lease should be split into three categories: lease components (e.g. land, building, etc.), non-lease components (e.g. common area maintenance, consumables, etc.), and non-components (e.g. property taxes, insurance, etc.). Subsequently, the fixed and in-substance fixed contract consideration (including any related to non-components) must be allocated based on the respective relative fair values to the lease components and non-lease components. The Company made the policy election to not separate lease and non-lease components. Each lease component and the related non-lease components are accounted for together as a single component.
Revenue Recognition	Revenue Recognition The Company adopted ASC 606, Revenue from Contracts with Customers Revenue Recognition The Company generates revenue from the sale of instruments, consumable diagnostic tests, related services, reagent rental agreements, research and development agreements with third parties and government contributions. Pursuant to ASC 606, revenue is recognized when a customer obtains control of promised goods or services. The amount of revenue recognized reflects the consideration the Company expects to be entitled to receive in exchange for these goods and services. Once a contract is determined to be within the scope of ASC 606 at contract inception, the Company reviews the contract to determine which performance obligations the Company must deliver and which of these performance obligations are distinct. The Company recognizes as revenues the amount of the transaction price that is allocated to the respective performance obligation when the performance obligation is satisfied or as it is satisfied. Generally, the Company's performance obligations are transferred to customers at a point in time, typically upon shipment, or over time, as services are performed. Most of the Company’s contracts with distributors in geographic regions outside the United States contain only a single performance obligation; whereas, most of the Company’s contracts with direct sales customers in the United States contain multiple performance obligations. For these contracts, the Company accounts for individual performance obligations separately if they are distinct. The transaction price is allocated to the separate performance obligations on a relative standalone selling price basis. Excluded from the transaction price are sales tax and other similar taxes which are presented on a net basis. Product revenue is generated by the sale of instruments and consumable diagnostic tests predominantly through the Company’s direct sales force in the United States and distributors in geographic regions outside the United States. The Company does not offer product return or exchange rights (other than those relating to defective goods under warranty) or price protection allowances to its customers, including its distributors. Payment terms granted to distributors are the same as those granted to end-user customers and payments are not dependent upon the distributors’ receipt of payment from their end-user customers. The Company either sells instruments to customers and international distributors, or retains title and places the instrument at the customer site pursuant to a reagent rental agreement. When an instrument is purchased by a customer, the Company recognizes revenue when the related performance obligation is satisfied (i.e. when the control of an instrument has passed to the customer; typically, at shipping point). When the instrument is placed under a reagent rental agreement, the Company’s customers generally agree to fixed term agreements, which can be extended, and incremental charges on each consumable diagnostic test purchased. Revenue from the sale of consumable diagnostic tests is recognized upon shipment. The transaction price from consumables purchases (under a reagent rental agreement) is allocated between the lease of the instrument (under a contingent rent methodology as provided for in ASC 842), and the consumables when related performance obligations are satisfied, as a component of lease and product revenue, and is included as Instrument Rentals in the below table. Revenue associated with reagent rental consumables purchases is currently classified as variable consideration and constrained until a purchase order is received and related performance obligations have been satisfied. Shipping and handling costs billed to customers in connection with a product sale are recorded as a component of the transaction price and allocated to product revenue in the consolidated statements of operations and comprehensive loss as they are incurred by the Company in fulfilling its performance obligations. Direct sales of instruments include warranty, maintenance and technical support services typically for one year following the installation of the purchased instrument (“Maintenance Services”). Maintenance Services are separate performance obligations as they are service based warranties and are recognized on a straight-line basis over the service delivery period. After the completion of the initial Maintenance Services period, customers have the option to renew or extend the Maintenance Services typically for additional Fees paid to member-owned group purchasing organizations (“GPOs”) are deducted from related product revenues. The Company warrants that consumable diagnostic tests will be free from defects, when handled according to product specifications, for the stated life of the product. To fulfill valid warranty claims, the Company provides replacement product free of charge. Accordingly, the Company accrues warranty expense associated with the estimated defective rates of the consumable diagnostic tests. Revenue earned from activities performed pursuant to research and development agreements is reported as research revenue in the consolidated statements of operations and comprehensive loss, and is recognized over time using an input method as the work is completed. The related costs are expensed as incurred as research and development expense. The timing of receipt of cash from the Company’s research and development agreements generally differs from when revenue is recognized. Milestones are contingent on the occurrence of future events and are considered variable consideration being constrained until the Company believes a significant revenue reversal will not occur. Refer to Note 15 for further details regarding the Company’s research and development arrangements. The Company adopted ASU No. 2018-08, Not-For-Profit Entities – Clarifying the Scope and the Accounting Guidance for Contributions Received and Contributions Made (“ASU 2018-08”) on January 1, 2019. According to ASU 2018-08, g The reported results for 2019 reflect the application of ASU 2018-08 as Disaggregation of Revenue The Company disaggregates revenue from contracts with customers by type of products and services, as it best depicts how the nature, amount, timing and uncertainty of revenue and cash flows are affected by economic factors. The following table disaggregates total revenue by major source (in thousands): 2019 2018 Product Revenue Instruments $ 2,280 $ 1,895 Consumables 2,863 2,387 Instrument Rentals 184 523 Total Product Revenue 5,327 4,805 Research Revenue 563 5,695 Contribution Revenue 2,445 — Total Revenue $ 8,335 $ 10,500 Remaining Performance Obligations Remaining performance obligations represent the transaction price of firm orders for which work has not been performed or goods and services have not been delivered. As of December 31, 2019 and 2018, the aggregate amount of transaction price allocated to remaining performance obligations for contracts with an original duration greater than one year was $0.2 million and $3.7 million, respectively, of which $3.0 million is constrained revenue in 2018. We do not disclose the value of unsatisfied performance obligations for (i) contracts with an original expected length of one year or less and (ii) contracts for which we recognize revenue at the amount to which we have the right to invoice for services performed. The Company expects to recognize revenue on the remaining performance obligations over the next 2 years. Significant Judgments Certain contracts with customers include promises to transfer multiple products and services to a customer. Determining whether products and services are considered distinct performance obligations that should be accounted for separately versus together may require significant judgment. Once we determine the performance obligations, the Company determines the transaction price, which includes estimating the amount of variable consideration, based on the most likely amount, to be included in the transaction price, if any. We then allocate the transaction price to each performance obligation in the contract based on a relative stand-alone selling price method. The corresponding revenue is recognized as the related performance obligations are satisfied as discussed in the revenue categories above. Judgment is required to determine the standalone selling price for each distinct performance obligation. We determine standalone selling price based on the price at which the performance obligation is sold separately. If the standalone selling price is not observable through past transactions, we estimate the standalone selling price taking into account available information such as market conditions and the expected costs and margin related to the performance obligations. Contract Assets and Liabilities The Company did not record any contract assets at December 31, 2019 and 2018. The Company’s contract liabilities consist of upfront payments for research and development contracts and maintenance services on instrument sales. We classify these contract liabilities in deferred revenue as current or noncurrent based on the timing of when we expect to recognize revenue. At December 31, 2019 and 2018, the Company had contract liabilities of $0.2 million and $0.6 million, respectively. Revenue recognized in the year-ended December 31, 2019 relating to contract liabilities at December 31, 2018 was $0.6 million, and related to performance of research and development services and straight-line revenue recognition associated with maintenance agreements. Cost to Obtain and Fulfill a Contract The Company does not meet the recoverability criteria to capitalize costs to obtain or fulfill instrument purchases. Reagent rental agreements do not meet the recoverability criteria to capitalize costs to obtain the contracts and the costs to fulfill the contracts are under the scope of ASC 842. At the end of each reporting period, the Company assesses whether any circumstances have changed to meet the criteria for capitalization. The Company did not incur any expenses to obtain research and development agreements and costs to fulfill those contracts do not generate or enhance resources of the entity. As such, no costs to obtain or fulfill contracts have been capitalized at period end.
Cost of Product Revenue	Cost of Product Revenue Cost of product revenue includes the cost of materials, direct labor and manufacturing overhead costs used in the manufacture of consumable diagnostic tests sold to customers and related license and royalty fees. Cost of product revenue also includes depreciation on revenue generating T2Dx instruments that have been placed with customers under reagent rental agreements; costs of materials, direct labor and manufacturing overhead costs on the T2Dx instruments sold to customers; and other costs such as customer support costs, royalties and license fees, warranty and repair and maintenance expense on the T2Dx instruments that have been placed with customers under reagent rental agreements.
Research and Development Costs	Research and Development Costs Costs incurred in the research and development of the Company’s product candidates are expensed as incurred. Research and development expenses consist of costs incurred in performing research and development activities, including activities associated with performing services under research revenue arrangements, costs associated with the manufacture of developed products and include salaries and benefits, stock compensation, research‑related facility and overhead costs, laboratory supplies, equipment and contract services.
Impairment of Long-lived Assets	Impairment of Long-lived Assets The Company reviews long‑lived assets, including capitalized T2 owned instruments and components, for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If indications of impairment exist, projected future undiscounted cash flows associated with the asset or asset group are compared to the carrying amount to determine whether the asset’s value is recoverable. During this review, the Company reevaluates the significant assumptions used in determining the original cost and estimated lives of long‑lived assets. Although the assumptions may vary from asset to asset, they generally include operating results, changes in the use of the asset, cash flows and other indicators of value. Management then determines whether the remaining useful life continues to be appropriate or whether there has been an impairment of long‑lived assets based primarily upon whether expected future undiscounted cash flows are sufficient to support the assets’ recovery. If impairment exists, the Company would adjust the carrying value of the asset to fair value, generally determined by a discounted cash flow analysis. If the carrying value of the asset exceeds such projected undiscounted cash flows, the asset will be written down to its estimated fair value.
Comprehensive Loss	Comprehensive Loss Comprehensive loss is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non‑owner sources. Comprehensive loss consists of net loss and other comprehensive loss, which includes certain changes in equity that are excluded from net loss. The Company’s comprehensive loss equals reported net loss for all periods presented.
Stock Based Compensation	Stock-Based Compensation The Company records stock‑based compensation for options granted to employees and to members of the Board of Directors for their services on the Board of Directors, based on the grant date fair value of awards issued, and the expense is recorded on a straight‑line basis over the requisite service period, which is generally four years. The Company accounts for non‑employee stock‑based compensation arrangements based upon the fair value of the consideration received or the equity instruments issued, whichever is more reliably measurable. The measurement date for non‑employee awards is generally the date that the performance of services required for the non‑employee award is complete. Stock‑based compensation costs for non‑employee awards is recognized as services are provided, which is generally the vesting period, on a straight‑line basis. The Company records the expense for stock option grants that vest upon achievement of performance-based milestones using the accelerated attribution method over the remaining service period when management determines that achievement of the performance-based milestone is probable. Management evaluates when the achievement of a performance-based milestone is probable based on the relative satisfaction of the performance conditions as of the reporting date. The Company expenses restricted stock awards and restricted stock units based on the fair value of the award on the date of issuance, on a straight‑line basis over the associated service period of the award. The Company uses the Black‑Scholes‑Merton option pricing model to determine the fair value of stock options. The use of the Black‑Scholes‑Merton option‑pricing model requires management to make assumptions with respect to the expected term of the option, the expected volatility of the common stock consistent with the expected life of the option, risk‑free interest rates and expected dividend yields of the common stock. The expected term was determined according to the simplified method, which is the average of the vesting tranche dates and the contractual term. Due to the lack of company specific historical and implied volatility data resulting from the Company’s limited public market trading history, prior to August 2018, the Company had based its estimate of expected volatility primarily on the historical volatility of a group of similar companies that are publicly traded. For these analyses, companies with comparable characteristics are selected, including enterprise value and position within the industry, and with historical share price information sufficient to meet the expected life of the stock‑based awards. The Company computes the historical volatility data using the daily closing prices for the selected companies’ shares during the equivalent period of the calculated expected term of its stock‑based awards. As of August 2018, the Company determined that a sufficient amount of historical information regarding the volatility of its stock price was available and estimated expected volatility based on the historical volatility of the Company’s stock using the daily closing prices. The risk‑free interest rate is determined by reference to U.S. Treasury zero‑coupon issues with remaining maturities similar to the expected term of the options. The Company has not paid, and does not anticipate paying, cash dividends on shares of common stock; therefore, the expected dividend yield is assumed to be zero. The Company has elected an accounting policy to estimate forfeitures at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from those estimates. The Company uses a Monte Carlo simulation to determine the fair value of restricted stock units with market conditions on the date of grant. The compensation cost for restricted stock units with market conditions is being recorded over the derived service period. If a market condition is achieved prior to completion of the derived service period, the remaining compensation cost will be recognized immediately. Refer to Note 8 for further details on the Company’s stock-based compensation plan.
Income Taxes	Income Taxes The Company provides for income taxes using the liability method. The Company provides deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the Company’s financial statement carrying amounts and the tax basis of assets and liabilities using enacted tax rates expected to be in effect in the years in which the differences are expected to reverse. A valuation allowance is provided to reduce the deferred tax assets to the amount that will more likely than not be realized. The Company applies ASC 740 Income Taxes The Tax Cuts and Jobs Act (the “Act”) was enacted on December 22, 2017. The Act reduces the US federal corporate tax rate from 35% to 21%, requires companies to pay a one-time transition tax on earnings of certain foreign subsidiaries that were previously tax deferred and creates new taxes on certain foreign sourced earnings. On December 22, 2017, the Securities and Exchange Commission (the “SEC”) issued guidance under Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act (“SAB 118”) directing taxpayers to consider the impact of the U.S. legislation as “provisional” when it does not have the necessary information available, prepared or analyzed (including computations) in reasonable detail to complete its accounting for the change in tax law. As of December 31, 2018, the Company did not recognize a provisional amount for the transition tax. For the year ended December 31, 2019, the Company recognized no transition tax, have remeasured deferred taxes, and included its reassessment of uncertain tax positions and valuation allowances. Management considers the accounting related to the Act to be final.
Guarantees	Guarantees As permitted under Delaware law, the Company indemnifies its officers and directors for certain events or occurrences while each such officer or director is, or was, serving at the Company’s request in such capacity. The term of the indemnification is 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’ liability insurance coverage that limits its exposure and enables the Company 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 landlords 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. In the ordinary course of business, the Company enters into indemnification agreements with certain suppliers and business partners where the Company has certain indemnification obligations limited to the costs, expenses, fines, suits, claims, demands, liabilities and actions directly resulting from the Company’s gross negligence or willful misconduct, and in certain instances, breaches, violations or nonperformance of covenants or conditions under the agreements. As of December 31, 2019 and 2018, 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.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is calculated by dividing net loss by the weighted-average number of shares of common stock 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 purposes of the diluted net loss per share calculation, stock options, unvested restricted stock and restricted stock contingently issuable upon achievement of certain market conditions are considered to be common stock equivalents, but have been excluded from the calculation of diluted net loss per share, as their effect would be anti-dilutive for all periods presented. Therefore, basic and diluted net loss per share applicable to common stockholders was the same for all periods presented.
Recent Accounting Standards	Recent Accounting Standards From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on its financial position or results of operations upon adoption. Accounting Standards Adopted In February 2016, the FASB issued ASU 2016-02, Leases (“ASU 2016-02”) in order to increase transparency and comparability among organizations by recognizing right-of-use assets and lease liabilities on the balance sheet for those leases classified as operating leases under previous generally accepted accounting principles. ASU 2016-02 requires a lessee to recognize a lease liability for future lease payments and a right-of-use asset representing the right to use the underlying asset for the lease term on the balance sheet for most lease arrangements. The new standard also changes many key definitions, including the definition of a lease. The new standard includes a short-term lease exception for leases with a term of 12 months or less, as part of which a lessee can make an accounting policy election not to recognize right-of-use assets and lease liabilities. Lessees will continue to differentiate between finance leases (previously referred to as capital leases) and operating leases using classification criteria that are substantially similar to the previous guidance in ASC 840. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018 (including interim periods within those periods) and early adoption is permitted. In August 2018, the FASB issued ASU 2018-11, Leases, Targeted Improvements In calculating the present value of the lease payments, the Company applied an individual discount rate for each of its leases, and determined the appropriate discount rate based on the remaining lease terms at the date of adoption. As the lessee to several lease agreements, the Company did not have insight into the relevant information that would be required to arrive at the rate implicit in the lease. Therefore, the Company utilized its outstanding borrowings as a benchmark to determine the incremental borrowing rate for its leases. The benchmark rate was adjusted to arrive at an appropriate discount rate for each lease. Under the new guidance, lessor accounting is largely unchanged. As of December 31, 2019, the Company was the lessor of T2Dx instruments. The lease agreements typically do not include fixed rental payments, but rather rental revenue is earned through usage-based variable lease payments. In accordance with ASC 842 the Company recognized lease revenue related to variable lease payments in the period in which it was earned. For the year ended December 31, 2019, the Company recognized $0.2 million of lease revenue for instrument rentals. In June 2018, the FASB issued ASU No. 2018-07, Compensation-Stock Compensation: Improvements to Nonemployee Share-Based Payment Accounting Compensation – Stock Compensation In June 2018, the FASB issued ASU No. 2018-08, Not-For-Profit Entities – Clarifying the Scope and the Accounting Guidance for Contributions Received and Contributions Made Accounting Standards Issued, Not Adopted In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses: Measurement of Credit Losses on Financial Instruments In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement In November 2018, the FASB issued ASU No. 2018-18, Collaborative Arrangements In December 2019, the FASB issued ASU No. 2019-12, Income Taxes: Simplifying the Accounting for Income Taxes

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Schedule of inventory	The components of inventory consist of the following (in thousands): December 31, December 31, 2019 2018 Raw materials $ 1,617 $ 639 Work-in-process 1,227 1,713 Finished goods 755 325 Total inventories, net $ 3,599 $ 2,677
Disaggregation of Total Revenue by Major Source	The following table disaggregates total revenue by major source (in thousands): 2019 2018 Product Revenue Instruments $ 2,280 $ 1,895 Consumables 2,863 2,387 Instrument Rentals 184 523 Total Product Revenue 5,327 4,805 Research Revenue 563 5,695 Contribution Revenue 2,445 — Total Revenue $ 8,335 $ 10,500

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Liabilities at Fair value on a Recurring Basis	The Company measures the following financial assets at fair value on a recurring basis. There were no transfers between levels of the fair value hierarchy during any of the periods presented. The following tables set forth the Company’s financial assets and liabilities carried at fair value categorized using the lowest level of input applicable to each financial instrument as of December 31, 2019 and 2018 (in thousands): Quoted Prices in Active Significant Markets for Other Significant Balance at Identical Observable Unobservable December 31, Assets Inputs Inputs 2019 (Level 1) (Level 2) (Level 3) Assets: Cash $ 6,732 $ 6,732 $ — $ — Money market funds 4,301 4,301 — — Restricted cash 180 180 — — $ 11,213 $ 11,213 $ — $ — Liabilities: Derivative liability $ 2,425 $ — $ — $ 2,425 $ 2,425 $ — $ — $ 2,425 Quoted Prices in Active Significant Markets for Other Significant Balance at Identical Observable Unobservable December 31, Assets Inputs Inputs 2018 (Level 1) (Level 2) (Level 3) Assets: Cash $ 6,868 $ 6,868 $ — $ — Money market funds $ 43,937 43,937 — — Restricted cash $ 180 180 — — $ 50,985 $ 50,985 $ — $ — Liabilities: Derivative liability $ 2,142 $ — $ — $ 2,142 $ 2,142 $ — $ — $ 2,142
Roll-Forward of Fair Value of Derivative Liability	The following table provides a roll-forward of the fair value of the derivative liability (in thousands): Balance at December 31, 2018 $ 2,142 Change in fair value of derivative liability, recorded as interest expense 283 Balance at December 31, 2019 $ 2,425

Supplemental Balance Sheet In_2

Supplemental Balance Sheet Information (Tables)	12 Months Ended
	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Schedule of Property and Equipment	Property and equipment consists of the following (in thousands) Estimated Useful December 31, December 31, Life (Years) 2019 2018 Office and computer equipment 3 $ 538 $ 409 Software 3 762 751 Laboratory equipment 5 4,747 4,636 Furniture 5-7 194 200 Manufacturing equipment 5 672 695 Manufacturing tooling and molds 0.5 255 255 T2-owned instruments and components 5 6,775 6,796 Leasehold improvements Lesser of useful life or remaining lease term 3,497 3,437 Construction in progress n/a 1,641 1,443 19,081 18,622 Less accumulated depreciation and amortization (13,236 ) (11,307 ) Property and equipment, net $ 5,845 $ 7,315
Components of Accrued Expenses	Accrued expenses consist of the following (in thousands): December 31, December 31, 2019 2018 Accrued payroll and compensation $ 3,193 $ 2,940 Accrued final fee 2,445 1,375 Accrued research and development expenses 267 359 Accrued professional services 511 576 Accrued interest 908 — Operating lease liabilities 1,983 — Other accrued expenses 1,900 823 Total accrued expenses and other current liabilities $ 11,207 $ 6,073

Notes Payable (Tables)

Notes Payable (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Schedule of Debt	Future principal payments on the notes payable as of December 31, 2019 are as follows (in thousands): Year ended December 31, 2020 $ — 2021 — 2022 48,077 2023 — 2024 — Total before unamortized discount and issuance costs 48,077 Less: paid-in-kind interest (3,284 ) Less: unamortized discount and issuance costs (1,891 ) Total notes payable $ 42,902

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock Option Activity	The following is a summary of option activity under the Stock Incentive Plans and Inducement Plan (in thousands, except share and per share amounts): Weighted-Average Weighted-Average Remaining Number of Exercise Price Per Contractual Term Aggregate Intrinsic Shares Share (In years) Value Outstanding at December 31, 2018 4,241,833 $ 6.98 7.02 $ 471 Granted 2,747,700 2.11 Exercised (2,119 ) 2.01 1 Forfeited (426,960 ) 5.06 Canceled (207,124 ) 8.62 Outstanding at December 31, 2019 6,353,330 4.95 7.29 229 Exercisable at December 31, 2019 3,242,751 6.84 5.55 33 Vested or expected to vest at December 31, 2019 5,751,313 $ 5.16 7.09 $ 199
Schedule of Estimated Assumptions Used to Calculate Weighted-Average Grant Date Fair Value of Options Granted	The total intrinsic value of options exercised in the year ended December 31, 2019 was immaterial. The total intrinsic value of options exercised in the years ended December 31, 2018 and 2017 were $1.4 million and $0.6 million, respectively. The weighted‑average fair values of options granted in the years ended December 31, 2019, 2018, and 2017 were $1.41, $3.54, and $2.95 per share, respectively, and were calculated using the following estimated assumptions: Year ended December 31, 2019 2018 2017 Weighted-average risk-free interest rate 1.97 % 2.67 % 1.99 % Expected dividend yield 0.00 % 0.00 % 0.00 % Expected volatility 78 % 68 % 60 % Expected terms 6.0 years 6.0 years 6.0 years
Schedule of Nonvested Restricted Stock Units Activity	The following is a summary of restricted stock unit activity under the 2014 Plan (in thousands, except share and per share amounts): Weighted-Average Number of Grant Date Fair Shares Value Nonvested at December 31, 2018 1,198,634 $ 5.04 Granted 589,142 3.23 Vested (189,129 ) 6.41 Forfeited (303,139 ) 4.33 Canceled — — Nonvested at December 31, 2019 1,295,508 $ 4.19
Schedule of Estimated Assumptions Used to Calculate Weighted-Average Fair Value of the Purchase Rights Granted	The fair value of the purchase rights granted under this plan was estimated on the date of grant and uses the following weighted-average assumptions, which were derived in a manner similar to those discussed in Note 2 relative to stock options: Year ended December 31, 2019 2018 2017 Weighted-average risk-free interest rate 2.44 % 2.24 % 1.03 % Expected dividend yield 0.00 % 0.00 % 0.00 % Expected volatility 71 % 70 % 68 % Expected terms 0.5 years 0.5 years 0.5 years
Summary of Stock-Based Compensation Expense for Stock Options Granted that was Recorded in the Company's Results of Operations	The following table summarizes the stock-based compensation expense resulting from awards granted under Stock Incentive Plans, the Inducement Plan and 2014 ESPP, that was recorded in the Company’s results of operations for the years presented (in thousands): Year ended December 31, 2019 2018 2017 Cost of product revenue $ 365 $ 803 $ 125 Research and development 1,184 1,603 1,384 Selling, general and administrative 3,888 7,362 3,196 Total stock-based compensation expense $ 5,437 $ 9,768 $ 4,705

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Net Loss Per Share Applicable to Common Stockholders	The following table presents the calculation of basic and diluted net loss per share applicable to common stockholders (in thousands, except share and per share data): Year ended December 31, 2019 2018 2017 Numerator: Net loss $ (59,006 ) $ (51,153 ) $ (62,428 ) Denominator: Weighted-average number of common shares outstanding — basic and diluted 45,507,754 40,558,826 32,131,512 Net loss per share applicable to common stockholders — basic and diluted $ (1.30 ) $ (1.26 ) $ (1.94 )
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following shares were excluded from the calculation of diluted net loss per share applicable to common stockholders, prior to the application of the treasury stock method, because their effect would have been anti ‑ Year ended December 31, 2019 2018 2017 Options to purchase common shares 6,353,330 4,241,833 3,785,083 Restricted stock units 1,295,508 1,198,634 606,497 Warrants to purchase common stock 1,097,249 528,958 528,958 Total 8,746,087 5,969,425 4,920,538

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Reconciliation of the U.S. Federal Statutory Rate to the Company's Effective Tax Rate	The reconciliation of the U.S. federal statutory rate to the Company’s effective tax rate is as follows: Year Ended December 31, 2019 2018 2017 Tax at statutory rates 21.0 % 21.0 % 35.0 % State income taxes 2.6 3.6 6.5 Permanent differences (1.2 ) (0.6 ) (2.5 ) Research and development credits 1.0 1.0 1.5 US tax rate change — - (52.7 ) Change in valuation allowance (23.4 ) (25.0 ) 12.2 Effective tax rate 0.0 % 0.0 % 0.0 %
Schedule Of Deferred Tax Assets	The significant components of the Company’s deferred tax asset consist of the following at December 31, 2019 and 2018 (in thousands): December 31, 2019 2018 Deferred tax assets: Net operating loss carryforwards $ 86,990 $ 73,612 Tax credits 8,329 7,603 Other temporary differences 2,888 3,156 Start-up expenditures 2,716 3,026 Stock option expenses 3,450 3,130 Lease liability 987 — Total deferred tax assets 105,360 90,527 Deferred tax asset valuation allowance (104,204 ) (90,361 ) Net deferred tax assets 1,156 166 Deferred tax liabilities: Right of use asset (859 ) — Prepaid expenses (297 ) (166 ) Net deferred taxes $ — $ —

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Schedule of Lease Cost	The following table summarizes the effect of operating and finance lease costs in the Company’s consolidated statement of operations and comprehensive loss (in thousands): Lease cost Year ended December 31, 2019 Finance lease cost: Amortization of right-of-use assets $ 235 Interest on lease liabilities 36 Operating lease cost 1,995 Variable lease cost 659 Total lease cost $ 2,925
Schedule of Other Information Related to Leases	The following table summarizes supplemental information for the Company’s finance and operating leases: Other information Year ended December 31, 2019 Weighted-average remaining lease term - operating leases (in years) 1.9 years Weighted-average discount rate - operating leases 11.9 %
Schedule of Maturity of Lease Liabilities	The minimum lease payments for the next five years and thereafter is expected to be as follows (in thousands): December 31, 2019 Maturity of lease liabilities Operating Leases 2020 $ 2,314 2021 1,951 2022 23 2023 — 2024 — Thereafter — Total lease payments $ 4,288 Less: effect of discounting (432 ) Present value of lease liabilities $ 3,856
Summary of Lease Assets and Liabilities	The following table summarizes the presentation of the Company’s operating leases in its consolidated balance sheets (in thousands): Leases Classification December 31, 2019 Assets Operating lease assets Operating lease assets 3,360 Total lease assets $ 3,360 Liabilities Current Operating Accrued expenses and other current liabilities $ 1,983 Noncurrent Operating Noncurrent operating lease liabilities 1,873 Total lease liabilities $ 3,856
Schedule of Future Minimum Lease Payments under the Company’s Operating Leases	Under ASC 840, future minimum non-cancelable lease payments under the Company’s operating leases as of December 31, 2018 were as follows (in thousands): Year ending December 31, 2019 $ 2,225 2020 2,277 2021 1,926 $ 6,428

Quarterly Financial Data (una_2

Quarterly Financial Data (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Schedule of quarterly financial information	Year ended December 31, 2019 (In thousands, except per share data) First Quarter Second Quarter Third Quarter Fourth Quarter Revenue: Product revenue $ 1,314 $ 1,274 $ 1,177 $ 1,562 Research revenue 142 71 56 294 Contribution revenue 329 459 444 1,213 Total revenue $ 1,785 $ 1,804 $ 1,677 $ 3,069 Costs and expenses: Cost of product revenue 4,388 4,820 3,944 3,611 Research and development 3,901 4,048 4,098 4,279 Selling, general and administrative 7,055 6,722 5,981 7,546 Total costs and expenses 15,344 15,590 14,023 15,436 Loss from operations $ (13,559 ) $ (13,786 ) $ (12,346 ) $ (12,367 ) Net loss $ (15,147 ) $ (15,647 ) $ (14,171 ) $ (14,041 ) Per share data: Net loss per common share—basic and diluted $ (0.34 ) $ (0.35 ) $ (0.31 ) $ (0.29 ) Year ended December 31, 2018 (In thousands, except per share data) First Quarter Second Quarter Third Quarter Fourth Quarter Revenue: Product revenue $ 1,048 $ 1,220 $ 1,218 $ 1,319 Research revenue 1,263 2,711 1,248 473 Total revenue $ 2,311 $ 3,931 $ 2,466 $ 1,792 Costs and expenses: Cost of product revenue 3,273 3,458 3,042 5,631 Research and development 4,718 3,749 2,725 3,297 Selling, general and administrative 5,755 7,611 5,873 6,458 Total costs and expenses 13,746 14,818 11,640 15,386 Loss from operations $ (11,435 ) $ (10,887 ) $ (9,174 ) $ (13,594 ) Net loss $ (12,913 ) $ (12,324 ) $ (10,767 ) $ (15,149 ) Per share data: Net loss per common share—basic and diluted $ (0.36 ) $ (0.32 ) $ (0.25 ) $ (0.34 )

Nature of Business - Additional

Nature of Business - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	2 Months Ended	12 Months Ended
	Mar. 13, 2020	Dec. 31, 2019	Jul. 29, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Nature of Business
Cash and cash equivalents		$ 11,033		$ 50,805	$ 41,799
Accumulated deficit		(376,177)		(317,171)
Stockholders’ deficit		(34,005)		$ 11,387	$ 1,340	$ 39,338
Term Loan Agreement [Member] | CRG [Member]
Nature of Business
Minimum cash balance		5,000
Sales Agreement [Member] | Canaccord [Member]
Nature of Business
Proceeds from issuance of common stock	$ 29,400	$ 6,700
Purchase Agreement [Member] | Lincoln Park Capital Fund, LLC [Member] | Minimum [Member]
Nature of Business
Stock price		$ 1	$ 1

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail)	Jan. 01, 2019USD ($)lease_arrangement	Dec. 31, 2019USD ($)Item	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)Item	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2019USD ($)SegmentItem	Dec. 31, 2018USD ($)Item	Dec. 31, 2017USD ($)
Product Information [Line Items]
Number of operating segments | Segment										1
Total revenue		$ 3,069,000	$ 1,677,000	$ 1,804,000	$ 1,785,000	$ 1,792,000	$ 2,466,000	$ 3,931,000	$ 2,311,000	$ 8,335,000	$ 10,500,000	$ 4,666,000
Outstanding receivable		$ 2,825,000				$ 1,786,000				$ 2,825,000	$ 1,786,000
Number of financial institutions in which cash was deposited | Item		1				1				1	1
Aggregate amount of transaction price allocated to remaining performance obligations for contracts with original duration greater than one year		$ 200,000				$ 3,700,000				$ 200,000	$ 3,700,000
Remaining performance obligation, expected timing of satisfaction										The Company expects to recognize revenue on the remaining performance obligations over the next 2 years.
Contract assets		0				0				$ 0	0
Contract liabilities		200,000				600,000				200,000	$ 600,000
Revenue recognized relating to contract liabilities										600,000
Costs to obtain or fulfill contract capitalized		0								$ 0
Expected dividend yield										0.00%
US federal corporate tax rate										21.00%	21.00%	35.00%
Transition tax recognized										$ 0	$ 0
Operating lease liabilities		3,856,000								3,856,000
Right-of-use assets		3,360,000								3,360,000
Co Development Partnership Agreement [Member] | CARB-X [Member]
Product Information [Line Items]
Total revenue										$ 900,000	$ 1,100,000
Accounting Standards Update 2016-02 [Member]
Product Information [Line Items]
Maximum short-term lease exception period										12 months
Number of operating lease arrangements | lease_arrangement	8
Number of finance lease arrangements | lease_arrangement	2
Operating lease liabilities	$ 5,600,000
Right-of-use assets	4,800,000
Accrued rent liability	$ 800,000
Minimum [Member]
Product Information [Line Items]
Aggregate amount of transaction price allocated to remaining performance obligations, original duration										1 year	1 year
Maximum [Member]
Product Information [Line Items]
Original expected period of contracts for which value of unsatisfied performance obligations not to be disclosed										1 year	1 year
T2 Dx [Member]
Product Information [Line Items]
Maintenance Services period (in years)										1 year
Additional period for Maintenance Service option (in years)										1 year
Constrained Revenue [Member]
Product Information [Line Items]
Aggregate amount of transaction price allocated to remaining performance obligations for contracts with original duration greater than one year						3,000,000					$ 3,000,000
Instrument Rentals [Member]
Product Information [Line Items]
Total revenue										$ 184,000	523,000
Lease revenue										200,000
Contribution [Member]
Product Information [Line Items]
Total revenue		1,213,000	$ 444,000	$ 459,000	$ 329,000					2,445,000
Contribution [Member] | Co Development Partnership Agreement [Member] | Biomedical Advanced Research and Development Authority [Member]
Product Information [Line Items]
Total revenue										1,500,000
Non-US [Member]
Product Information [Line Items]
Total revenue										2,800,000	2,200,000	$ 900,000
Outstanding receivable		$ 1,200,000				$ 900,000				$ 1,200,000	$ 900,000
Revenue [Member] | Geographic Concentration Risk [Member] | Non-US [Member]
Product Information [Line Items]
Total revenue (as a percent)										34.00%	21.00%	19.00%
Revenue [Member] | Customer Concentration Risk [Member] | Customer One [Member]
Product Information [Line Items]
Total revenue (as a percent)										19.00%	29.00%	19.00%
Revenue [Member] | Customer Concentration Risk [Member] | Customer Two [Member]
Product Information [Line Items]
Total revenue (as a percent)										11.00%	15.00%	10.00%
Revenue [Member] | Customer Concentration Risk [Member] | Customer Three [Member]
Product Information [Line Items]
Total revenue (as a percent)										8.00%	10.00%
Accounts Receivable [Member] | Customer Concentration Risk [Member] | Customer One [Member]
Product Information [Line Items]
Total revenue (as a percent)										27.00%	25.00%
Accounts Receivable [Member] | Customer Concentration Risk [Member] | Customer Two [Member]
Product Information [Line Items]
Total revenue (as a percent)										10.00%	22.00%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Components of Inventory (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Inventory Net [Abstract]
Raw materials	$ 1,617	$ 639
Work-in-process	1,227	1,713
Finished goods	755	325
Total inventories, net	$ 3,599	$ 2,677

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Disaggregation of Total Revenue by Major Resource (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation Of Revenue [Line Items]
Total revenue	$ 3,069	$ 1,677	$ 1,804	$ 1,785	$ 1,792	$ 2,466	$ 3,931	$ 2,311	$ 8,335	$ 10,500	$ 4,666
Product Instruments [Member]
Disaggregation Of Revenue [Line Items]
Total revenue									2,280	1,895
Product Consumables [Member]
Disaggregation Of Revenue [Line Items]
Total revenue									2,863	2,387
Instrument Rentals [Member]
Disaggregation Of Revenue [Line Items]
Total revenue									184	523
Total Product Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	1,562	1,177	1,274	1,314	1,319	1,218	1,220	1,048	5,327	4,805	3,440
Research [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	$ 294	$ 56	$ 71	$ 142	$ 473	$ 1,248	$ 2,711	$ 1,263	563	$ 5,695	$ 1,226
Contribution Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenue									$ 2,445

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets and Liabilities at Fair value on a Recurring Basis (Detail) - Estimate of Fair Value Measurement [Member] - Recurring [Member] - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Assets:
Restricted cash	$ 180	$ 180
Total assets	11,213	50,985
Liabilities:
Derivative liability	2,425	2,142
Total Liabilities	2,425	2,142
Cash [Member]
Assets:
Cash	6,732	6,868
Money Market Funds [Member]
Assets:
Cash	4,301	43,937
Level 1 [Member]
Assets:
Restricted cash	180	180
Total assets	11,213	50,985
Level 1 [Member] | Cash [Member]
Assets:
Cash	6,732	6,868
Level 1 [Member] | Money Market Funds [Member]
Assets:
Cash	4,301	43,937
Level 3 [Member]
Liabilities:
Derivative liability	2,425	2,142
Total Liabilities	$ 2,425	$ 2,142

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2019	Mar. 31, 2019	Aug. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2022	Jan. 01, 2021
Certificates of deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Certificates of deposit classified as restricted cash	$ 180,000	$ 180,000						$ 180,000
CRG [Member] | Term Loan Agreement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Additional interest rate, event of default (as a percent)								4.00%
Debt instrument covenant compliance revenue targeted for fiscal year	140,000,000	95,000,000	$ 4,000,000	$ 9,000,000	$ 9,000,000			$ 4,000,000
Derivative liability	$ 2,400,000	$ 2,100,000						$ 2,400,000
CRG [Member] | Term Loan Agreement [Member] | Scenario Forecast [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument covenant compliance revenue targeted for fiscal year						$ 43,000,000	$ 15,000,000		$ 43,000,000	$ 15,000,000
CRG [Member] | Term Loan Agreement [Member] | Contingent Interest Beginning in 2020 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent payment of interest rate								4.00%
CRG [Member] | Term Loan Agreement [Member] | Contingent Interest Beginning in 2020 [Member] | Measurement Input, Discount Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of discount rate								70.00%
CRG [Member] | Term Loan Agreement [Member] | Contingent Interest Beginning in 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent payment of interest rate								4.00%
CRG [Member] | Term Loan Agreement [Member] | Contingent Interest Beginning in 2021 | Measurement Input, Discount Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of discount rate								30.00%

Fair Value Measurements - Roll-

Fair Value Measurements - Roll-Forward of Fair Value of Derivative Liability (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Change in fair value of derivative liability, recorded as interest expense	$ 283	$ (96)	$ 2,238
Probability-Weighted Discounted Cash Flow Model [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance at December 31, 2018	2,142
Change in fair value of derivative liability, recorded as interest expense	283
Balance at December 31, 2019	$ 2,425	$ 2,142

Restricted Cash - Additional In

Restricted Cash - Additional Information (Detail) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Certificates of deposit [Member]
Restricted Cash And Cash Equivalents Items [Line Items]
Security deposit	$ 180,000	$ 180,000

Supplemental Balance Sheet In_3

Supplemental Balance Sheet Information - Schedule of Property and Equipment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 19,081	$ 18,622
Less accumulated depreciation and amortization	(13,236)	(11,307)
Property and equipment, net	$ 5,845	7,315
Office and Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	3 years
Property and equipment, gross	$ 538	409
Software [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	3 years
Property and equipment, gross	$ 762	751
Laboratory Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	5 years
Property and equipment, gross	$ 4,747	4,636
Furniture [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 194	200
Furniture [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	5 years
Furniture [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	7 years
Manufacturing Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	5 years
Property and equipment, gross	$ 672	695
Manufacturing Tooling and Molds [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	6 months
Property and equipment, gross	$ 255	255
T2-Owned Instruments and Components [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	5 years
Property and equipment, gross	$ 6,775	6,796
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	3,497	3,437
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,641	$ 1,443

Supplemental Balance Sheet In_4

Supplemental Balance Sheet Information - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Supplemental Balance Sheet Information [Line Items]
Raw materials and work-in-process inventory		$ 600,000	$ 300,000
Depreciation and amortization		2,197,000	2,449,000	$ 2,940,000
Property and equipment, net		5,845,000	7,315,000
Property and equipment, gross		19,081,000	18,622,000
Accumulated depreciation and amortization for property and equipment		13,236,000	11,307,000
Transfer from other liabilities to accrued expenses and other current liabilities related to fee from debt		2,400,000	1,400,000	$ 585,000
Other accrued expenses		1,900,000	823,000
Accrued payroll and compensation		3,193,000	2,940,000
Transition Agreement [Member]
Supplemental Balance Sheet Information [Line Items]
Other accrued expenses		1,000,000
Accrued payroll and compensation		$ 200,000
T2 Owned Instruments in Service [Member]
Supplemental Balance Sheet Information [Line Items]
Estimated useful lives (in years)		5 years
T2 Owned Instruments in Service [Member] | Product [Member]
Supplemental Balance Sheet Information [Line Items]
Depreciation expense recorded as a component of cost of product revenue		$ 800,000	1,000,000
Finance\Capital Leases Assets [Member]
Supplemental Balance Sheet Information [Line Items]
Property and equipment, net		0
Repurchase of equipment		$ 300,000
Property and equipment, gross			3,600,000
Accumulated depreciation and amortization for property and equipment			2,600,000
T2-Owned Instruments and Components [Member]
Supplemental Balance Sheet Information [Line Items]
Estimated useful lives (in years)		5 years
Property and equipment, gross		$ 6,775,000	6,796,000
Impairment charges	$ 2,600,000
T2 Candida 1.1 Cartridge [Member]
Supplemental Balance Sheet Information [Line Items]
Impairment charges			$ 700,000

Supplemental Balance Sheet In_5

Supplemental Balance Sheet Information - Components of Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accrued Liabilities Current [Abstract]
Accrued payroll and compensation	$ 3,193	$ 2,940
Accrued final fee	2,445	1,375
Accrued research and development expenses	267	359
Accrued professional services	511	576
Accrued interest	908
Operating lease liabilities	1,983
Other accrued expenses	1,900	823
Total accrued expenses and other current liabilities	$ 11,207	$ 6,073

Notes Payable - Schedule of Deb

Notes Payable - Schedule of Debt (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Notes Payable [Abstract]
2022	$ 48,077
Total before unamortized discount and issuance costs	48,077
Less: paid-in-kind interest	(3,284)
Less: unamortized discount and issuance costs	(1,891)
Total notes payable	$ 42,902	$ 42,373

Notes Payable - Term Loan Agree

Notes Payable - Term Loan Agreement - Additional Information (Detail) - USD ($)

Dec. 31, 2019

Dec. 31, 2018

Sep. 30, 2019

Mar. 31, 2019

Dec. 31, 2016

Aug. 31, 2019

Dec. 31, 2022

Dec. 31, 2021

Dec. 31, 2020

Dec. 31, 2019

Jan. 01, 2022

Jan. 01, 2021

Common Stock [Member]

Debt Instrument

Number of shares issuable for warrants outstanding (in shares)

568,291

528,958

Exercise price of warrants

$ 1.55

$ 4.35

$ 8.06

CRG [Member] | Term Loan Agreement [Member]

Debt Instrument

Proceeds from issuance of long-term debt

$ 40,000,000

Debt term (in years)

6 years

Debt instrument, term of interest-only payments (in years)

3 years

Final fee as a percentage of the principal outstanding (as a percent)

10.00%

8.00%

8.00%

Debt instrument, prepayment fee term (in years)

5 years

Debt instrument covenant compliance revenue targeted for fiscal year

$ 140,000,000

$ 95,000,000

$ 4,000,000

$ 9,000,000

$ 9,000,000

$ 4,000,000

Additional interest rate, event of default (as a percent)

4.00%

Derivative liability

$ 2,400,000

$ 2,100,000

$ 2,400,000

CRG [Member] | Term Loan Agreement [Member] | Achieving Approval Milestone [Member]

Debt Instrument

Extended period of debt instrument, term of interest-only payments (in years)

4 years

CRG [Member] | Term Loan Agreement [Member] | Prior to Approval Milestone [Member]

Debt Instrument

Annual fixed rate (as a percent)

12.50%

Deferred interest rate (as a percent)

4.00%

CRG [Member] | Term Loan Agreement [Member] | Following Approval Milestone [Member]

Debt Instrument

Annual fixed rate (as a percent)

11.50%

Deferred interest rate (as a percent)

3.50%

CRG [Member] | Term Loan Agreement [Member] | Scenario Forecast [Member]

Debt Instrument

Debt instrument, quarterly principal payment

$ 12,000,000

Debt instrument covenant compliance revenue targeted for fiscal year

$ 43,000,000

$ 15,000,000

$ 43,000,000

$ 15,000,000

Notes Payable - Equipment Lease

Notes Payable - Equipment Lease Credit Facility - Additional Information (Detail) - Finance Lease Obligations [Member]	1 Months Ended			12 Months Ended
	Jun. 30, 2016USD ($)Draw	Apr. 30, 2016USD ($)	Oct. 31, 2015USD ($)	Dec. 31, 2019USD ($)
Debt Instrument
Initial borrowing capacity			$ 10,000,000
Maximum borrowings available (up to)			$ 5,000,000
Debt term (in months)			36 months
Repurchase price as percentage of original equipment value that the equipment under lease may be repurchased by lessee			10.00%
Minimum lease period to extend lease (in years)			1 year
Amount of draw	$ 2,500,000	$ 2,100,000
Amount of monthly payment	$ 79,000	$ 67,000
Number of draws | Draw	2
Repurchase of equipment				$ 300,000

Stockholders' (Deficit) Equity

Stockholders' (Deficit) Equity - Additional Information (Detail)	Jul. 30, 2019USD ($)	Jul. 29, 2019USD ($)$ / sharesshares	Jun. 04, 2018USD ($)$ / sharesshares	Sep. 15, 2017USD ($)$ / sharesshares	Mar. 13, 2020USD ($)	Dec. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2018Item$ / sharesshares
Class Of Stock [Line Items]
Number of voting rights per share of common stock | Item							1
Common stock, par value (in dollars per share) | $ / shares						$ 0.001	$ 0.001
Common stock, shares authorized						200,000,000	200,000,000
Common stock, shares outstanding						50,651,535	44,175,441
Sales Agreement [Member] | Canaccord [Member]
Class Of Stock [Line Items]
Sale of common stock authorized, amount | $	$ 30,000,000
Percentage of agent service fee	3.00%
Number of shares issued/sold						5,486,500
Proceeds from issuance of common stock | $					$ 29,400,000	$ 6,700,000
Purchase Agreement [Member] | Lincoln Park Capital Fund, LLC [Member]
Class Of Stock [Line Items]
Sale of common stock authorized, amount | $		$ 30,000,000
Number of shares issued/sold		413,349
Effective period for sale of common stock		36 months
Maximum number of shares issue per business day		200,000
Maximum amount of shares to be issue per business day | $		$ 2,000,000
Purchase Agreement [Member] | Lincoln Park Capital Fund, LLC [Member] | Minimum [Member]
Class Of Stock [Line Items]
Stock price | $ / shares		$ 1				$ 1
Public Offering [Member]
Class Of Stock [Line Items]
Number of shares issued/sold			7,015,000	5,031,250
Proceeds from issuance of common stock | $			$ 52,600,000	$ 20,100,000
Sale price of stock (in dollars per share) | $ / shares			$ 7.50	$ 4
Proceeds from issuance of common stock after underwriters discount and expenses | $			$ 49,200,000	$ 18,800,000
Options to Purchase Common Shares [Member]
Class Of Stock [Line Items]
Common stock reserved for issuance						6,353,330
Issuance of Stock Awards [Member]
Class Of Stock [Line Items]
Common stock reserved for issuance						1,397,186
Exercise of Warrants [Member]
Class Of Stock [Line Items]
Common stock reserved for issuance						1,097,249

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)	Jan. 08, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Mar. 31, 2018
Share-Based Compensation
Fair value of vested stock options		$ 3,100,000	$ 3,000,000	$ 3,500,000
Stock-based compensation expense		$ 5,437,000	9,768,000	4,705,000
T2-Owned Instruments and Components [Member]
Share-Based Compensation
Stock-based compensation expense			100,000	100,000
Employee Stock Purchase Plan [Member]
Share-Based Compensation
Shares available for grant		142,432
Shares available for authorization		220,588
Percentage of full share price paid in purchase of common stock		85.00%
Maximum amount of annual employee common stock purchases		$ 25,000
Stock-based compensation expense		$ 400,000	400,000	200,000
Number of shares purchased by participants		306,824
Number of shares available for grant description		In addition, on the first day of each calendar year beginning January 1, 2015 and ending on January 1, 2024, the number of common shares available under the 2014 ESPP shall be increased by the number of shares equal to the lesser of (1) 220,588 shares, (2) 1% of the common shares outstanding on the final day of the immediately preceding calendar year and (3) such smaller number of common shares as determined by the Board of Directors.
Percentage of common shares outstanding		1.00%
Subsequent Event [Member]
Share-Based Compensation
Increase in shares available for grant	4,000,000
Restricted Stock Units [Member]
Share-Based Compensation
Weighted-average period		2 years
Unrecognized compensation cost related to unvested stock options		$ 1,300,000
2014 Stock Option Plan [Member] | Stock Options [Member]
Share-Based Compensation
Shares available for future issuance under stock incentive plan		823,529
Percentage of common shares outstanding		4.00%
Shares available for grant		537,754
2014 Stock Option Plan [Member] | Restricted Stock Units [Member]
Share-Based Compensation
Restricted stock units vested		189,129
Restricted stock units granted		589,142
Inducement Award Plan [Member]
Share-Based Compensation
Shares available for grant		717,000
Shares available for authorization					1,625,000
Inducement Award Plan [Member] | Subsequent Event [Member]
Share-Based Compensation
Shares available for grant	5,625,000
2006 and 2014 Stock Option Plans [Member] | Stock Options [Member]
Share-Based Compensation
Aggregate fair value of options granted		$ 3,900,000	5,800,000	2,700,000
Unrecognized compensation cost related to non-vested stock options		$ 5,800,000
Weighted-average period		2 years 7 months 6 days
2006 and 2014 Stock Option Plans and Inducement Plan [Member] | Stock Options [Member]
Share-Based Compensation
Total intrinsic value of options exercised		$ 1,000	$ 1,400,000	$ 600,000
Weighted average fair value of options granted		$ 1.41	$ 3.54	$ 2.95
2006 and 2014 Stock Option Plans and Inducement Plan [Member] | Restricted Stock Units [Member]
Share-Based Compensation
Aggregate fair value of restricted stock units granted		$ 1,900,000
2006 and 2014 Stock Option Plans and Inducement Plan [Member] | Restricted Stock Units [Member] | Restricted Stock Units Vested, Reflected As Outstanding Shares [Member]
Share-Based Compensation
Restricted stock units vested			78,172
2006 and 2014 Stock Option Plans and Inducement Plan [Member] | Restricted Stock Units [Member] | Restricted Stock Units Vested, Not Reflected As Outstanding Shares [Member]
Share-Based Compensation
Restricted stock units vested			73,172
2006 and 2014 Stock Option Plans and Inducement Plan [Member] | Restricted Stock Units with Market Condition [Member]
Share-Based Compensation
Restricted stock units granted		755,168
Compensation Cost		$ 1,000,000	$ 4,500,000
Maximum [Member] | 2006 Stock Option Plan [Member] | Stock Options [Member]
Share-Based Compensation
Expiration period		10 years
Vesting period		4 years
Maximum [Member] | 2014 Stock Option Plan [Member] | Stock Options [Member]
Share-Based Compensation
Expiration period		10 years
Vesting period		4 years

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activity (Detail) - 2006 and 2014 Stock Option Plans and Inducement Plan [Member] - Stock Options [Member] - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-Based Compensation
Number of Shares Outstanding, beginning of the period	4,241,833
Number of Shares, Granted	2,747,700
Number of Shares, Exercised	(2,119)
Number of Shares, Forfeited	(426,960)
Number of Shares, Canceled	(207,124)
Number of Shares Outstanding, end of the period	6,353,330	4,241,833
Number of Shares, Exercisable	3,242,751
Number of Shares, Vested or expected to vest	5,751,313
Weighted-Average Exercise Price Per Share Outstanding, beginning of the period	$ 6.98
Weighted-Average Exercise Price Per Share, Granted	2.11
Weighted-Average Exercise Price Per Share, Exercised	2.01
Weighted-Average Exercise Price Per Share, Forfeited	5.06
Weighted-Average Exercise Price Per Share, Canceled	8.62
Weighted-Average Exercise Price Per Share Outstanding, end of the period	4.95	$ 6.98
Weighted-Average Exercise Price Per Share, Exercisable	6.84
Weighted-Average Exercise Price Per Share, Vested or expected to vest	$ 5.16
Weighted-Average Remaining Contractual Term, Outstanding	7 years 3 months 14 days	7 years 7 days
Weighted-Average Remaining Contractual Term, Exercisable	5 years 6 months 18 days
Weighted-Average Remaining Contractual Term, Vested or expected to vest	7 years 1 month 2 days
Aggregate Intrinsic Value, Outstanding, beginning of the period	$ 471
Aggregate Intrinsic Value, Exercised	1	$ 1,400	$ 600
Aggregate Intrinsic Value Outstanding, end of the period	229	$ 471
Aggregate Intrinsic Value, Exercisable	33
Aggregate Intrinsic Value, Vested or expected to vest	$ 199

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Estimated Assumptions Used to Calculate Weighted-Average Grant Date Fair Value of Options Granted (Detail)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-Based Compensation
Expected dividend yield	0.00%
Stock Options [Member] | 2006 and 2014 Stock Option Plans and Inducement Plan [Member]
Share-Based Compensation
Weighted-average risk-free interest rate	1.97%	2.67%	1.99%
Expected dividend yield	0.00%	0.00%	0.00%
Expected volatility	78.00%	68.00%	60.00%
Expected terms	6 years	6 years	6 years

Stock-Based Compensation - Sc_2

Stock-Based Compensation - Schedule of Nonvested Restricted Stock Units Activity (Detail) - 2014 Stock Option Plan [Member] - Restricted Stock Units [Member]	12 Months Ended
	Dec. 31, 2019$ / sharesshares
Share-Based Compensation
Number of Shares, Nonvested restricted shares at the beginning of the period | shares	1,198,634
Number of Shares, Restricted shares granted | shares	589,142
Number of Shares, Restricted shares vested | shares	(189,129)
Number of Shares, Restricted shares forfeited | shares	(303,139)
Number of Shares, Canceled | shares	0
Number of Shares, Nonvested restricted shares at the end of the period | shares	1,295,508
Weighted-Average Grant Date Fair Value, Nonvested restricted shares at the beginning of the period | $ / shares	$ 5.04
Weighted-Average Grant Date Fair Value, Granted | $ / shares	3.23
Weighted-Average Grant Date Fair Value, Vested | $ / shares	6.41
Weighted-Average Grant Date Fair Value, Forfeited | $ / shares	4.33
Weighted-Average Grant Date Fair Value, Canceled | $ / shares	0
Weighted-Average Grant Date Fair Value, Nonvested restricted shares at the end of the period | $ / shares	$ 4.19

Stock-Based Compensation - Sc_3

Stock-Based Compensation - Schedule of Estimated Assumptions Used to Calculate Weighted-Average Fair Value of the Purchase Rights Granted (Detail)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-Based Compensation
Expected dividend yield	0.00%
Employee Stock Purchase Plan [Member]
Share-Based Compensation
Weighted-average risk-free interest rate	2.44%	2.24%	1.03%
Expected dividend yield	0.00%	0.00%	0.00%
Expected volatility	71.00%	70.00%	68.00%
Expected terms	6 months	6 months	6 months

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Stock-Based Compensation Expense for Stock Options Granted that was Recorded in the Company's Results of Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock-based compensation expense
Stock-based compensation expense	$ 5,437	$ 9,768	$ 4,705
Cost of Product Revenue [Member]
Stock-based compensation expense
Stock-based compensation expense	365	803	125
Research and Development [Member]
Stock-based compensation expense
Stock-based compensation expense	1,184	1,603	1,384
Selling, General and Administrative [Member]
Stock-based compensation expense
Stock-based compensation expense	$ 3,888	$ 7,362	$ 3,196

Warrants - Additional Informati

Warrants - Additional Information (Detail) - Common Stock [Member] - USD ($) $ / shares in Units, $ in Millions	Aug. 31, 2019	Sep. 30, 2019	Mar. 31, 2019	Dec. 31, 2016
Class of Warrant or Right [Line Items]
Number of shares issuable for warrants outstanding		568,291		528,958
Exercise price of warrants		$ 1.55	$ 4.35	$ 8.06
Fair market value of amended warrants	$ 0.9	$ 0.1
Incremental fair value of warrants adjustment	$ 0.1	$ 0.7

Net Loss Per Share - Schedule o

Net Loss Per Share - Schedule of Basic and Diluted Net Loss Per Share Applicable to Common Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Numerator:
Net loss	$ (14,041)	$ (14,171)	$ (15,647)	$ (15,147)	$ (15,149)	$ (10,767)	$ (12,324)	$ (12,913)	$ (59,006)	$ (51,153)	$ (62,428)
Denominator:
Weighted-average number of common shares outstanding — basic and diluted									45,507,754	40,558,826	32,131,512
Net loss per share — basic and diluted	$ (0.29)	$ (0.31)	$ (0.35)	$ (0.34)	$ (0.34)	$ (0.25)	$ (0.32)	$ (0.36)	$ (1.30)	$ (1.26)	$ (1.94)

Net Loss Per Share - Schedule_2

Net Loss Per Share - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Detail) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the computation of diluted net loss per share	8,746,087	5,969,425	4,920,538
Options to Purchase Common Shares [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the computation of diluted net loss per share	6,353,330	4,241,833	3,785,083
Restricted Stock Units [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the computation of diluted net loss per share	1,295,508	1,198,634	606,497
Warrants to Purchase Common Stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the computation of diluted net loss per share	1,097,249	528,958	528,958

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation of the U.S. Federal Statutory Rate to the Company's Effective Tax Rate (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Effective Income Tax Rate Reconciliation, Percent.
Tax at statutory rates	21.00%	21.00%	35.00%
State income taxes	2.60%	3.60%	6.50%
Permanent differences	(1.20%)	(0.60%)	(2.50%)
Research and development credits	1.00%	1.00%	1.50%
US tax rate change			(52.70%)
Change in valuation allowance	(23.40%)	(25.00%)	12.20%
Effective tax rate	0.00%	0.00%	0.00%

Income Taxes - Schedule Of Defe

Income Taxes - Schedule Of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Net operating loss carryforwards	$ 86,990	$ 73,612
Tax credits	8,329	7,603
Other temporary differences	2,888	3,156
Start-up expenditures	2,716	3,026
Stock option expenses	3,450	3,130
Lease liability	987
Total deferred tax assets	105,360	90,527
Deferred tax asset valuation allowance	(104,204)	(90,361)
Net deferred tax assets	1,156	166
Deferred tax liabilities:
Right of use asset	(859)
Prepaid expenses	$ (297)	$ (166)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Line Items]
Increase (decrease) in valuation allowance	$ 13,800	$ 12,800
Unrecognized tax benefits	0
Accrued interest or penalties related to uncertain tax positions	0	$ 0
Federal [Member]
Income Taxes [Line Items]
Net operating losses	329,600
Net operating loss carryforwards, subject to expiration	$ 228,200
Net operating loss carryforwards, expiration date	Dec. 31, 2037
Net operating loss carryforwards, not subject to expiration	$ 101,400
Federal [Member] | Research and Development [Member]
Income Taxes [Line Items]
Credit carryforward	$ 5,500
Credit carryforward, expiration date	Dec. 31, 2039
State [Member]
Income Taxes [Line Items]
Net operating losses	$ 292,400
Net operating loss carryforwards, subject to expiration	$ 288,000
Net operating loss carryforwards, expiration date	Dec. 31, 2039
Net operating loss carryforwards, not subject to expiration	$ 4,400
State [Member] | Research and Development [Member]
Income Taxes [Line Items]
Credit carryforward	$ 3,600
Credit carryforward, expiration date	Dec. 31, 2034

Leases - Additional Information

Leases - Additional Information (Detail)

1 Months Ended

12 Months Ended

Aug. 31, 2018

Sep. 30, 2017

Mar. 31, 2017

Jun. 30, 2016USD ($)Draw

Apr. 30, 2016USD ($)

Oct. 31, 2015USD ($)

Apr. 30, 2015

Nov. 30, 2014USD ($)

Dec. 31, 2019USD ($)

Dec. 31, 2018USD ($)

Dec. 31, 2017USD ($)

Jan. 31, 2018USD ($)

Jan. 01, 2011USD ($)

Leases [Line Items]

Right-of-use assets

$ 3,360,000

Lease liabilities

3,856,000

Rent expenses

$ 2,000,000

$ 1,900,000

Finance Lease Obligations [Member]

Leases [Line Items]

Initial borrowing capacity

$ 10,000,000

Maximum borrowings available (up to)

$ 5,000,000

Debt term (in months)

36 months

Repurchase price as percentage of original equipment value that the equipment under lease may be repurchased by lessee

10.00%

Minimum lease period to extend lease (in years)

1 year

Amount of draw

$ 2,500,000

$ 2,100,000

Amount of monthly payment

$ 79,000

$ 67,000

Number of draws | Draw

2

Repurchase of equipment

300,000

Operating Lease Entered into November 2014 [Member] | License Agreement [Member] | Office Space [Member]

Leases [Line Items]

Lease expiration date

Dec. 31, 2021

Dec. 31, 2017

Security deposit

$ 50,000

Office Space, Laboratory Space, and Equipment [Member]

Leases [Line Items]

Right-of-use assets

0

Lease liabilities

$ 0

Maximum lease period to not recognize right of use assets or lease liabilities

12 months

Office and Laboratory Space [Member] | Operating Lease Entered into August 2010 [Member]

Leases [Line Items]

Lease expiration date

Dec. 31, 2021

Security deposit

$ 180,000

$ 400,000

Office, Laboratory and Manufacturing Space [Member] | Operating Lease Entered into May 2013 [Member]

Leases [Line Items]

Lease expiration date

Dec. 31, 2020

Laboratory Space [Member] | Operating Lease Entered into November 2014 [Member]

Leases [Line Items]

Security deposit

$ 281,000

Term of lease

6 years

Space build-out costs paid

$ 1,400,000

Space build-out costs

$ 2,200,000

Leases - Schedule of Lease Cost

Leases - Schedule of Lease Cost (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Finance lease cost:
Amortization of right-of-use assets	$ 235
Interest on lease liabilities	36
Operating lease cost	1,995
Variable lease cost	659
Total lease cost	$ 2,925

Leases - Schedule of Other Info

Leases - Schedule of Other Information Related to Leases (Detail)	Dec. 31, 2019
Leases [Abstract]
Weighted-average remaining lease term - operating leases (in years)	1 year 10 months 24 days
Weighted-average discount rate - operating leases	11.90%

Leases - Schedule of Maturity o

Leases - Schedule of Maturity of Lease Liabilities (Detail) $ in Thousands	Dec. 31, 2019USD ($)
Maturity of operating leases liabilities
2020	$ 2,314
2021	1,951
2022	23
Total lease payments	4,288
Less: effect of discounting	(432)
Present value of lease liabilities	$ 3,856

Leases - Summary of Lease Asset

Leases - Summary of Lease Assets and Liabilities (Detail) $ in Thousands	Dec. 31, 2019USD ($)
Schedule Of Lease Assets And Liabilities [Abstract]
Operating lease assets	$ 3,360
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OperatingLeaseRightOfUseAsset
Operating lease liabilities, Current	$ 1,983
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccruedLiabilitiesCurrent
Operating lease liabilities, Noncurrent	$ 1,873
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OperatingLeaseLiabilityNoncurrent
Total lease liabilities	$ 3,856

Leases - Future Minimum Lease P

Leases - Future Minimum Lease Payments (Detail) $ in Thousands	Dec. 31, 2019USD ($)
Future minimum lease payments
2019	$ 2,225
2020	2,277
2021	1,926
Total	$ 6,428

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($)	12 Months Ended	24 Months Ended
	Dec. 31, 2019	Dec. 31, 2007	Dec. 31, 2018	Dec. 31, 2006
Commitments and Contingencies [Line Items]
Accrued payroll and compensation	$ 3,193,000		$ 2,940,000
License Agreement [Member]
Commitments and Contingencies [Line Items]
Shares issued		84,678
Royalty on net sales sublicensing gross revenue	10.00%
Transition Agreement [Member]
Commitments and Contingencies [Line Items]
Payment period on transition and health benefits	15 months
Transition Agreement [Member] | Bonus [Member]
Commitments and Contingencies [Line Items]
Accrued payroll and compensation	$ 200,000
Transition Agreement [Member] | Other Accrued Expenses [Member]
Commitments and Contingencies [Line Items]
Transition payments and health benefits	$ 1,000,000
Minimum [Member] | License Agreement [Member]
Commitments and Contingencies [Line Items]
Annual license fee payable				$ 5,000
Percentage of royalty on net sales	0.50%
Maximum [Member] | License Agreement [Member]
Commitments and Contingencies [Line Items]
Annual license fee payable				$ 25,000
Percentage of royalty on net sales	3.50%

401(k) Savings Plan - Additiona

401(k) Savings Plan - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Compensation And Retirement Disclosure [Abstract]
Contributions to 401 (k) plan at the discretion of the board	$ 195,000	$ 126,000	$ 190,000

Co-Development Agreements - Add

Co-Development Agreements - Additional Information (Detail)	Nov. 01, 2016USD ($)specie	Sep. 21, 2016USD ($)	Feb. 03, 2015USD ($)Item	Jan. 31, 2019USD ($)	May 31, 2018USD ($)	Mar. 31, 2018USD ($)specie	Oct. 31, 2015USD ($)	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Jan. 01, 2018USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue								$ 3,069,000	$ 1,677,000	$ 1,804,000	$ 1,785,000	$ 1,792,000	$ 2,466,000	$ 3,931,000	$ 2,311,000	$ 8,335,000	$ 10,500,000	$ 4,666,000
Adjustment to opening accumulated deficit								(376,177,000)				$ (317,171,000)				(376,177,000)	(317,171,000)
Contribution [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue								1,213,000	444,000	$ 459,000	$ 329,000					2,445,000
Co Development Partnership Agreement [Member] | Canon U.S. Life Sciences Inc [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront payment			$ 2,000,000
Additional consideration receivable upon achievement of certain development and regulatory milestones			6,500,000
Aggregate consideration receivable			$ 8,500,000
Proceeds received for achievement of milestone					$ 2,000,000		$ 1,500,000
Final regulatory milestone will not achieve								$ 3,000,000								3,000,000
Number of units | Item			1
Revenue																500,000	1,500,000	300,000
Co Development Partnership Agreement [Member] | Allergan Sales [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront payment	$ 2,000,000
Revenue																0	3,100,000	$ 900,000
Number of additional bacteria species added to existing product candidate | specie	1
Additional milestone payments received	$ 4,000,000
Co Development Partnership Agreement [Member] | Allergan Sales [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Adjustment to opening accumulated deficit																			$ (100,000)
Co Development Partnership Agreement [Member] | CARB-X [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue																900,000	$ 1,100,000
Number of additional bacteria species added to existing product candidate | specie						20
Co Development Partnership Agreement [Member] | CARB-X [Member] | Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Aggregate consideration receivable						$ 2,000,000									$ 2,000,000
Collaborative arrangement reimbursement amount				$ 900,000		1,100,000
Milestone payment						$ 900,000
Co Development Partnership Agreement [Member] | Biomedical Advanced Research and Development Authority [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Initial value of consideration receivable									6,000,000
Co Development Partnership Agreement [Member] | Biomedical Advanced Research and Development Authority [Member] | Contribution [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue																$ 1,500,000
Co Development Partnership Agreement [Member] | Biomedical Advanced Research and Development Authority [Member] | Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Aggregate consideration receivable									$ 69,000,000
Private Placement [Member] | Canon U S A Inc [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Proceeds from sale of shares in related party		$ 39,700,000
Percentage of outstanding shares at date of sale		19.90%

Quarterly Financial Data (una_3

Quarterly Financial Data (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue:
Total revenue	$ 3,069	$ 1,677	$ 1,804	$ 1,785	$ 1,792	$ 2,466	$ 3,931	$ 2,311	$ 8,335	$ 10,500	$ 4,666
Costs and expenses:
Research and development	4,279	4,098	4,048	3,901	3,297	2,725	3,749	4,718	16,326	14,489	23,733
Selling, general and administrative	7,546	5,981	6,722	7,055	6,458	5,873	7,611	5,755	27,304	25,697	22,757
Total costs and expenses	15,436	14,023	15,590	15,344	15,386	11,640	14,818	13,746	60,393	55,590	58,518
Loss from operations	(12,367)	(12,346)	(13,786)	(13,559)	(13,594)	(9,174)	(10,887)	(11,435)	(52,058)	(45,090)	(53,852)
Net loss	$ (14,041)	$ (14,171)	$ (15,647)	$ (15,147)	$ (15,149)	$ (10,767)	$ (12,324)	$ (12,913)	$ (59,006)	$ (51,153)	$ (62,428)
Per share data:
Net loss per common share - basic and diluted (in dollars per share)	$ (0.29)	$ (0.31)	$ (0.35)	$ (0.34)	$ (0.34)	$ (0.25)	$ (0.32)	$ (0.36)	$ (1.30)	$ (1.26)	$ (1.94)
Product [Member]
Revenue:
Total revenue	$ 1,562	$ 1,177	$ 1,274	$ 1,314	$ 1,319	$ 1,218	$ 1,220	$ 1,048	$ 5,327	$ 4,805	$ 3,440
Costs and expenses:
Cost of product revenue	3,611	3,944	4,820	4,388	5,631	3,042	3,458	3,273	16,763	15,404	12,028
Research [Member]
Revenue:
Total revenue	294	56	71	142	$ 473	$ 1,248	$ 2,711	$ 1,263	563	$ 5,695	$ 1,226
Contribution [Member]
Revenue:
Total revenue	$ 1,213	$ 444	$ 459	$ 329					$ 2,445

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - Sales Agreement [Member] - Canaccord [Member] - USD ($)	Mar. 09, 2020	Jul. 30, 2019	Mar. 13, 2020	Dec. 31, 2019
Subsequent Event [Line Items]
Sale of common stock authorized, amount		$ 30,000,000
Number of shares issued/sold				5,486,500
Proceeds from issuance of common stock			$ 29,400,000	$ 6,700,000
Subsequent Event [Member]
Subsequent Event [Line Items]
Sale of common stock authorized, amount	$ 65,000,000
Number of shares issued/sold			49,401,624
Proceeds from issuance of common stock			$ 29,300,000