Paratek Pharmaceuticals (PRTK) 10-Q 11 May 20 2020 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2020	Apr. 30, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Trading Symbol	PRTK
Entity Registrant Name	PARATEK PHARMACEUTICALS, INC.
Entity Central Index Key	0001178711
Entity Current Reporting Status	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity File Number	001-36066
Entity Tax Identification Number	33-0960223
Entity Address, Address Line One	75 Park Plaza
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02116
City Area Code	617
Local Phone Number	807-6600
Entity Common Stock, Shares Outstanding		43,132,044
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, par value $0.001 per share
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 124,624	$ 102,302
Marketable securities	70,166	113,077
Restricted cash	630	324
Accounts receivable, net	10,887	8,475
Inventories, net	13,472	11,579
Other receivables	1,383	1,108
Prepaid and other current assets	5,844	6,489
Total current assets	227,006	243,354
Long-term restricted cash	2,261	3,007
Fixed assets, net	1,094	1,227
Goodwill	829	829
Right-of-use assets	2,322	2,514
Other long-term assets	148	148
Total assets	233,660	251,079
Current liabilities
Accounts payable	663	4,116
Accrued expenses	18,100	16,696
Current portion of long-term debt	20,751
Other current liabilities	3,595	3,388
Total current liabilities	43,109	24,200
Long-term debt	240,299	260,728
Long-term lease liabilities	1,838	2,095
Other liabilities	3,652	3,703
Total liabilities	288,898	290,726
Commitments and contingencies (Note 17)
Stockholders’ deficit
Undesignated preferred stock: $0.001 par value; 5,000,000 authorized; no shares issued and outstanding
Common stock, $0.001 par value, 100,000,000 shares authorized, 42,374,026 and 39,827,749 issued and outstanding at March 31, 2020 and December 31, 2019, respectively	42	40
Additional paid-in capital	683,124	671,497
Accumulated other comprehensive income	471	74
Accumulated deficit	(738,875)	(711,258)
Total stockholders’ deficit	(55,238)	(39,647)
Total liabilities and stockholders’ deficit	$ 233,660	$ 251,079

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) (unaudited) - $ / shares	Mar. 31, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Undesignated preferred stock, par value	$ 0.001	$ 0.001
Undesignated preferred stock, shares authorized	5,000,000	5,000,000
Undesignated preferred stock, shares issued	0	0
Undesignated preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	42,374,026	39,827,749
Common stock, shares outstanding	42,374,026	39,827,749

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Net revenue	$ 7,920	$ 1,598
Expenses:
Cost of product revenue	1,471	206
Research and development	6,389	11,392
Selling, general and administrative	23,638	23,316
Total operating expenses	31,498	34,914
Loss from operations	(23,578)	(33,316)
Other income and expenses:
Interest income	705	946
Interest expense	(4,826)	(3,226)
Other gains (losses), net	82	(14)
Net loss	(27,617)	(35,610)
Other comprehensive loss
Unrealized gain on available-for-sale securities, net of tax	397	200
Comprehensive loss	$ (27,220)	$ (35,410)
Basic and diluted net loss per common share	$ (0.66)	$ (1.10)
Weighted average common stock outstanding Basic and diluted	41,641,203	32,334,563
Product Revenue, Net [Member]
Net revenue	$ 7,303	$ 1,347
Government Contract Service Revenue [Member]
Net revenue	337
Collaboration and Royalty Revenue [Member]
Net revenue	$ 280	$ 251

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement Of Cash Flows [Abstract]
Net loss	$ (27,617)	$ (35,610)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation, amortization and accretion	70	(485)
Stock-based compensation expense	2,535	3,863
Noncash interest expense	4,542	2,748
Changes in operating assets and liabilities
Accounts receivable and other current assets	(2,079)	(2,348)
Purchase of prepaid interest - marketable securities	21
Inventories	(137)	(1,379)
Operating lease right-of-use asset	192	173
Accounts payable and accrued expenses	(7,758)	(1,776)
Operating lease liability	(256)	(990)
Other liabilities and other assets	161	48
Net cash used in operating activities	(30,326)	(35,756)
Investing activities
Purchase of fixed assets	(253)	(11)
Purchase of marketable securities	(19,631)
Proceeds from maturities of marketable securities	63,000	70,000
Net cash provided by investing activities	43,116	69,989
Financing activities
Proceeds from sale of common stock, net of costs	9,092
Net cash provided by financing activities	9,092
Net increase in cash, cash equivalents and restricted cash	21,882	34,233
Cash, cash equivalents and restricted cash at beginning of period	105,633	47,502
Cash, cash equivalents and restricted cash at end of period	127,515	81,735
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Cash paid for interest	2,463	$ 1,471
Purchases of equipment included in accrued expenses	$ 87

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity (Deficit) (unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]
Beginning balance at Dec. 31, 2018	$ 47,578	$ 32	$ 630,142	$ (128)	$ (582,468)
Beginning balance, shares at Dec. 31, 2018		32,259,363
Vesting of restricted stock unit awards, shares		156,614
Employee stock purchase plan expense	24		24
Unrealized gain on available-for-sale securities, net of tax	200			200
Stock-based compensation expense	3,839		3,839
Net loss	(35,610)				(35,610)
Ending balance at Mar. 31, 2019	16,031	$ 32	634,005	72	(618,078)
Ending balance, shares at Mar. 31, 2019		32,415,977
Beginning balance at Dec. 31, 2019	(39,647)	$ 40	671,497	74	(711,258)
Beginning balance, shares at Dec. 31, 2019		39,827,749
Issuance of common stock, net of expenses	9,094	$ 2	9,092
Issuance of common stock, net of expenses, shares		2,334,107
Vesting of restricted stock unit awards, shares		212,170
Employee stock purchase plan expense	35		35
Unrealized gain on available-for-sale securities, net of tax	397			397
Stock-based compensation expense	2,500		2,500
Net loss	(27,617)				(27,617)
Ending balance at Mar. 31, 2020	$ (55,238)	$ 42	$ 683,124	$ 471	$ (738,875)
Ending balance, shares at Mar. 31, 2020		42,374,026

Description of the Business

Description of the Business	3 Months Ended
	Mar. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Description of the Business	1. Description of the business Paratek Pharmaceuticals, Inc., or the Company or Paratek, is a Delaware corporation with its corporate office in Boston, Massachusetts and an office in King of Prussia, Pennsylvania. The Company is a commercial-stage biopharmaceutical company focused on the development and commercialization of novel life-saving therapies for life-threatening diseases or other public health threats for civilian, government and military use. The Company has used its expertise in biology and tetracycline chemistry to create chemically diverse and biologically distinct small molecules derived from the minocycline core structure. The Company’s United States, or U.S., Food and Drug Administration, or FDA, approved commercial product, NUZYRA ® ® Almirall plans to develop sarecycline for acne in China, with a submission to the China National Medical Products Administration, or NMPA, expected in 2023. The Company has incurred significant losses since inception in 1996. The Company has generated an accumulated deficit of $738.9 million through March 31, 2020 and may require substantial additional funding in connection with the Company’s continuing operations to support clinical development and commercialization activities associated with NUZYRA. Based upon the Company’s current operating plan, it anticipates that its cash, cash equivalents and available for sale marketable securities of $194.8 million as of March 31, 2020 will enable the Company to fund operating expenses and capital expenditure requirements through at least the next twelve months from the issuance of the financial statements included in this Quarterly Report on Form 10-Q

Summary of Significant Accounti

Summary of Significant Accounting Policies and Basis of Presentation	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies and Basis of Presentation	2. Summary of Significant Accounting Policies and Basis of Presentation Basis of Presentation The accompanying condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles, or U.S. GAAP, as found in the Accounting Standards Codification, or ASC, and Accounting Standards Updates, or ASU, of the Financial Accounting Standards Board, or FASB, and pursuant to the rules and regulations of the SEC. The accompanying condensed consolidated financial statements are unaudited. The unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements as of and for the year ended December 31, 2019, and, in the opinion of management, reflect all normal recurring adjustments necessary for the fair presentation of the Company’s financial position as of March 31, 2020 and December 31, 2019, results of operations for the three month periods ended March 31, 2020 and March 31, 2019, cash flows for the three month periods ended March 31, 2020 and March 31, 2019 and changes in stockholders’ deficit for the three month periods ended March 31, 2020 and March 31, 2019. The results of operations for the interim periods are not necessarily indicative of the results of operations to be expected for the year ending December 31, 2020. These unaudited interim condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements as of and for the year ended December 31, 2019, and notes thereto, which are included in the Company’s 2019 Form 10-K. Summary of Significant Accounting Policies As of Mach 31, 2020, the Company’s significant accounting policies and estimates, which are detailed in the Company’s 2019 Form 10-K, have not changed. Principles of Consolidation The accompanying unaudited condensed consolidated financial statements include the results of operations of Paratek Pharmaceuticals, Inc. and its wholly-owned subsidiaries, Paratek Pharma, LLC, Paratek Securities Corporation, Transcept Pharma , Inc., Use of Estimates The preparation of the accompanying unaudited condensed consolidated financial statements, in conformity with U.S. GAAP, requires the Company to make estimates and judgments that affect the reported amounts of assets, liabilities, and expenses and the disclosure of contingent liabilities in the Company’s financial statements. On an ongoing basis, the Company evaluates its estimates and judgments, including those related to, manufacturing and clinical accruals, Changes in estimates are reflected in reported results in the period in which they become known by the Company’s management. Segment and Geographic Information Operating segments are defined as components of an enterprise engaging in business activities for which discrete financial information is available and regularly reviewed by the chief operating decision maker in deciding how to allocate resources and in assessing performance. The Company views its operations and manages its business in one operating segment. Concentration of Credit Risk Financial instruments that subject the Company to credit risk consist primarily of cash, restricted cash, and accounts receivable. The Company places its cash in an accredited financial institution and this balance is above federally insured amounts. The Company has no off-balance sheet concentrations of credit risk such as foreign currency exchange contracts, option contracts or other hedging arrangements. Accounts receivable as of March 31, 2020 represents $7.2 million due from customers on sales of NUZYRA, net of prompt payment discounts, chargebacks, rebates and certain fees, as well as a $3.0 million milestone earned during the year ended December 31, 2019, but not yet received, under the Zai Collaboration Agreement (as defined below). The balance of accounts receivable as of March 31, 2020, includes revenue earned, but not yet received, of $0.4 million of royalties on SEYSARA sales under the Almirall Collaboration Agreement (as defined below) and XERAVA TM Government, License and Collaboration Agreements

Cash and Cash Equivalents and M

Cash and Cash Equivalents and Marketable Securities	3 Months Ended
	Mar. 31, 2020
Cash And Cash Equivalents [Abstract]
Cash and Cash Equivalents and Marketable Securities	3. Cash and Cash Equivalents and Marketable Securities The following is a summary of available-for-sale securities as of March 31, 2020 and December 31, 2019 (in thousands): Amortized Cost Unrealized Gains Unrealized Losses Fair Value March 31, 2020 U.S. treasury securities $ 69,695 $ 471 $ — $ 70,166 Total $ 69,695 $ 471 $ $ 70,166 December 31, 2019 U.S. treasury securities $ 113,003 $ 89 $ (15 ) $ 113,077 Total $ 113,003 $ 89 $ (15 ) $ 113,077 No available-for-sale securities held as of March 31, 2020 and December 31, 2019 had remaining maturities greater than twelve months.

Restricted Cash

Restricted Cash	3 Months Ended
	Mar. 31, 2020
Restricted Cash And Investments [Abstract]
Restricted Cash	4. Restricted Cash The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the condensed consolidated statement of cash flows that sum to the total of the same such amounts shown in the condensed consolidated statement of cash flows (in thousands): March 31, 2020 March 31, 2019 Cash and cash equivalents $ 124,624 $ 81,219 Short-term restricted cash 630 266 Long-term restricted cash 2,261 250 Total cash, cash equivalents and restricted cash shown on the condensed consolidated statement of cash flows $ 127,515 $ 81,735 Short-term restricted cash On May 1, 2019, the Company deposited $4.0 million into an interest reserve account in conjunction with the funding of a royalty-backed loan agreement, or the Royalty-Backed Loan Agreement, executed with Healthcare Royalty Partners III, L.P. Payments of interest under the Royalty-Backed Loan Agreement are made quarterly using royalty payments received since the immediately preceding payment date under the Almirall Collaboration Agreement, as defined in Note 8, Government, License and Collaboration Agreements Long-Term Debt, for further details. Long-term restricted cash The Company leases its Boston, Massachusetts office space under a non-cancelable operating lease. Refer to Note 14, Leases In accordance with the lease, the Company has a cash-collateralized irrevocable standby letter of credit in the amount of $0.3 million as of both March 31, 2020 and December 31, 2019, naming the landlord as beneficiary. As of March 31, 2020 and December 31, 2019, long term restricted cash of $2.0 million and $2.7 million, respectively, represented the remaining balance in the interest reserve account that is expected to be paid to Healthcare Royalty Partners III, L.P. after March 31, 2021.

Inventories, Net

Inventories, Net	3 Months Ended
	Mar. 31, 2020
Inventory Disclosure [Abstract]
Inventories, Net	5. Inventories, Net The following table presents inventories, net (in thousands): March 31, 2020 December 31, 2019 Work in process $ 9,598 $ 9,330 Finished goods 3,874 2,249 Total inventories, net $ 13,472 $ 11,579 When recorded, inventory reserves reduce the carrying value of inventories to their net realizable value. The Company reviews inventories on hand at least quarterly and records provisions for estimated excess, slow-moving and obsolete inventory, as well as inventory with a carrying value in excess of net realizable value.

Fixed Assets, Net

Fixed Assets, Net	3 Months Ended
	Mar. 31, 2020
Property Plant And Equipment [Abstract]
Fixed Assets, Net	6. Fixed Assets, Net Fixed assets, net, consists of the following (in thousands): March 31, 2020 December 31, 2019 Office equipment $ 866 $ 866 Machinery and equipment 567 567 Computer equipment 412 412 Computer software 798 798 Leasehold improvements 920 920 Gross fixed assets 3,563 3,563 Less: Accumulated depreciation and amortization (2,469 ) (2,336 ) Total fixed assets, net $ 1,094 $ 1,227

Net Loss Per Share

Net Loss Per Share	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Net Loss Per Share	7. Net Loss Per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common stock outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common share equivalents outstanding for the period determined using the treasury-stock method or the if-converted method, as applicable. For purposes of this calculation, shares of common stock issuable upon conversion of convertible debt, stock options, restricted stock units, warrants to purchase common stock, and shares issuable under the employee stock purchase plan are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive. The following outstanding shares subject to stock options and restricted stock units, warrants to purchase shares of common stock, common stock issuable upon conversion of convertible debt and shares issuable under the employee stock purchase plan were antidilutive due to a net loss in the periods presented and, therefore, were excluded from the dilutive securities computation as of the three months ended March 31, 2020 and 2019 as indicated below: Three Months Ended March 31, 2020 2019 Excluded potentially dilutive securities (1) Common stock issuable under outstanding convertible notes 10,377,361 10,377,361 Shares subject to outstanding options to purchase common stock 3,309,900 3,815,951 Unvested restricted stock units 4,444,454 2,837,588 Shares subject to warrants to purchase common stock 104,455 104,455 Shares issuable under employee stock purchase plan 798,187 979,833 Totals 19,034,357 18,115,188 (1) The number of shares is based on the maximum number of shares issuable on exercise or conversion of the related securities as of March 31, 2020

Government, License and Collabo

Government, License and Collaboration Agreements	3 Months Ended
	Mar. 31, 2020
Text Block [Abstract]
Government, License and Collaboration Agreements	8. Government, License and Collaboration Agreements Biomedical Advanced Research and Development Authority On December 18, 2019, the Company entered into a five-year contract with the Biomedical Advanced Research and Development Authority, or BARDA, a division of the U.S. Department of Health and Human Services’ Office of the Assistant Secretary for Preparedness and Response, herein referred to as the BARDA contract, with an option to extend up to ten years, to support the development of NUZYRA for the treatment of pulmonary anthrax, FDA post-marketing requirements, or PMRs, associated with the initial NUZYRA approval, and with an option for BARDA to procure up to 10,000 treatment courses of NUZYRA for the Strategic National Stockpile, or SNS. The BARDA contract could result in payments to the Company of up to approximately $284.7 million and consists of a five-year base period-of-performance and a total contract period-of-performance (base period plus option exercises) of up to ten years. Under the base period-of-performance, the Company will conduct activities necessary to (i) allow the product to be used under an Emergency Use Authorization (ii) obtain licensure of NUZYRA through a supplemental New Drug Application, or NDA, submission for anthrax, and (iii) provide up to 2,500 treatment courses of the drug product to be stored as vendor managed inventory and subsequently delivered to the SNS. The contract options may be exercised to perform additional studies necessary for licensure, support post-licensure commitments as required by the FDA, additional security requirements, and procure additional treatment regimens. Under the terms of the agreement, BARDA awarded initial funding of approximately $59.4 million for the development of NUZYRA for the treatment of pulmonary anthrax and the purchase of an initial 2,500 treatment courses of NUZYRA to add to the current SNS. The contract provides for additional staged funding, including approximately $76.8 million for existing FDA PMR commitments that began in April 2020 and approximately $20.4 million for manufacturing-related requirements, which also began in April 2020. BARDA exercised the options to award the initial funding in December 2019 and the additional staged funding in April 2020. The additional staged funding will support all FDA PMRs associated with the approval of NUZYRA, including CABP and pediatric studies as well as a five-year post-marketing bacterial surveillance study, and support the U.S. onshoring and security requirements of Paratek manufacturing activities for NUZYRA. The remaining funding under the BARDA contract includes the potential for approximately $12.7 million to support the development of NUZYRA for the prophylaxis of anthrax and a maximum of approximately $115.4 million to provide for three additional purchases of NUZYRA, each of which will be triggered upon development milestones related to the anthrax treatment development program. The BARDA contract contains a number of terms and conditions that are customary for government contracts of this nature, including provisions giving the government the right to terminate the contract at any time for its convenience. The Company recognized $0.3 million of government contract service revenue Tetraphase Pharmaceuticals, Inc. On March 18, 2019, Paratek and Tetraphase Pharmaceuticals, Inc., or Tetraphase, entered into a License Agreement, or the Tetraphase License Agreement. Under the terms of the Tetraphase License Agreement, Paratek granted to Tetraphase a non-exclusive, worldwide, royalty-bearing license, with the right to grant sublicenses, under certain Paratek patents, to develop, make, have, use, import, offer for sale and sell the licensed product, or XERAVA, which is a drug for the treatment of complicated, intra-abdominal infections caused by bacteria, which was approved by the FDA in August 2018. The terms of the Tetraphase License Agreement provide for Tetraphase to pay Paratek royalties at a low single digit percent on net product revenues of the licensed product sold in the U.S. Tetraphase’s obligation to pay royalties with respect to the licensed product shall be retroactive to the date of the first commercial sale of the licensed product in the U.S., which occurred in February 2019. Tetraphase is currently selling XERAVA in the U.S. The Tetraphase License Agreement will continue until the expiration of and payment by Tetraphase of all Tetraphase’s payment obligations, which is when there are no longer any valid claims of the licensed Paratek patents that would be infringed, in the absence of a license, by a manufacture, use, or sales of the licensed product. The principal licensed patent under the Tetraphase License Agreement is expected to expire in October 2023. The Company recognized an insignificant amount of royalty revenue for the three months ended March 31, 2020 and 2019 under the Tetraphase License Agreement. Zai Lab (Shanghai) Co., Ltd. On April 21, 2017, Paratek Bermuda Ltd., a wholly-owned subsidiary of Paratek Pharmaceuticals, Inc., and Zai entered into a License and Collaboration Agreement, or the Zai Collaboration Agreement. On December 18, 2019 Paratek Bermuda Ltd. assigned its rights under the Zai Collaboration Agreement to Paratek Pharmaceuticals, Inc. Under the terms of the Zai Collaboration Agreement, Paratek granted Zai an exclusive license to develop, manufacture and commercialize omadacycline, or the licensed product, in the PRC, Hong Kong, Macau and Taiwan, or the Zai territory, for all human therapeutic and preventative uses other than biodefense. Zai will be responsible for the development, manufacturing and commercialization of the licensed product in the Zai territory, at its sole cost with certain assistance from Paratek. Under the terms of the Zai Collaboration Agreement, Paratek earned an upfront cash payment of $7.5 million in April 2017, $5.0 million upon approval by the FDA of a New Drug Application, or NDA, submission in the CABP indication, in October 2018, and $3.0 million upon submission of the first regulatory approval application for a licensed product in the PRC in December 2019. T he Center for Drug Evaluation of China’s granted priority review status to the NDA submitted by Zai regulatory approval for a licensed product in the PRC The Zai Collaboration Agreement will continue, on a region-by-region basis, until the expiration of and payment by Zai of all Zai’s payment obligations, which is until the later of: (i) the abandonment, expiry or final determination of invalidity of the last valid claim within the Paratek patents that covers the licensed product in the region in the Zai territory in the manner that Zai or its affiliates or sublicensees exploit the licensed product or intend for the licensed product to be exploited; or (ii) the eleventh anniversary of the first commercial sale of such licensed product in such region. The Company evaluated the Zai Collaboration Agreement under ASC Topic 606, Revenue from Contracts with Customers The Company determined that the exclusive license and initial technology transfer were not distinct from one another, as the license has limited value without the transfer of the Company’s technology; which will allow . Without the technology transfer, Zai would incur additional costs to recreate the Company’s know-how. Therefore, the license and initial technology transfer are combined as a single performance obligation. The transfer of materials is a single distinct performance obligation. The Company evaluated the option rights for manufacturing services, regulatory support and commercialization support to determine whether they represent or include material rights to Zai and concluded that the options were not issued at a discount, and therefore do not represent material rights. As such, they are not considered performance obligations at the outset of the arrangement. Based on these assessments, the Company determined that two performance obligations existed at the outset of the Zai Collaboration Agreement: (i) the exclusive license combined with the initial technology transfer and (ii) the transfer of certain materials. The Company satisfied both performance obligations and recognized the upfront payment of $7.5 million as revenue in the year ended December 31, 2017. Future potential milestone payments were excluded from the transaction price as they are fully constrained as the risk of significant reversal has not yet been resolved. The achievement of the future potential milestones is not within the Company’s control and is subject to certain research and development success or regulatory approvals and therefore carry significant uncertainty. The Company will reevaluate the likelihood of achieving future milestones at the end of each reporting period. As all performance obligations have been satisfied, if the risk of significant reversal is resolved, any future milestone revenue from the arrangement will be recognized as revenue in the period the risk is relieved. As FDA approval was not within the control of the Company and was not obtained until October 2018, the achievement of the milestone was not deemed probable and the risk of significant reversal of revenue was not resolved until that time. Upon the FDA approval, the uncertainty related to this milestone was resolved and a significant reversal of revenue would not occur in future periods. As such, the $5.0 million milestone payment was recognized as revenue at the time of FDA approval in the fourth quarter of 2018. As submission of the first regulatory approval application for a licensed product in the PRC is not within the control of the Company and was not obtained until December 2019, the achievement of the milestone was not was not deemed probable and the risk of significant reversal of revenue was not resolved until that time. Upon submission, the uncertainty related to this milestone was resolved and a significant reversal of revenue would not occur in future periods. As such, the $3.0 million milestone payment was recognized as revenue at the time of the regulatory approval application submission in the fourth quarter of 2019. As regulatory approval in the PRC is not within the control of the Company, the achievement of the milestone was not deemed probable and the risk of significant reversal of revenue was not resolved as of March 31, 2020. As such, the next milestone payment was not recognized as revenue in the year ended December 31, 2019 or the three months ended March 31, 2020. Almirall, LLC In July 2007, the Company and Warner Chilcott Company, Inc. (which became a part of Allergan plc, or Allergan), entered into a collaborative research and license agreement under which the Company granted Allergan an exclusive license to research, develop, manufacture and commercialize tetracycline products for use in the U.S. for the treatment of acne and rosacea. In September 2018, Allergan assigned to Almirall its rights under the collaboration agreement, or the Almirall Collaboration Agreement. Since Allergan did not exercise its development option with respect to the treatment of rosacea prior to initiation of a Phase 3 trial for the product, the license grant to Allergan, which was assigned to Almirall, converted to a non-exclusive license for the treatment of rosacea as of December 2014. Under the terms of the Almirall Collaboration Agreement, Almirall is responsible for and is obligated to use commercially reasonable efforts to develop and commercialize tetracycline compounds that are specified in the agreement for the treatment of acne. The Company has agreed during the term of the Almirall Collaboration Agreement not to directly or indirectly develop or commercialize any tetracycline compounds in the U.S. for the treatment of acne, and Almirall has agreed during the term of the Almirall Collaboration Agreement not to directly or indirectly develop or commercialize any tetracycline compound included as part of the agreement for any use other than as provided in the Almirall Collaboration Agreement. In February 2020, the Company finalized a license agreement with Almirall granting the Company exclusive rights to develop, manufacture and commercialize sarecycline outside of the U.S., including rights of reference to Almirall’s clinical data thus formalizing the Company’s rights to develop, manufacture and commercialize sarecycline in the rest of the world. In connection with that license, the Company then exclusively licensed Almirall pursuant to the Almirall China License Agreement, the rights to develop, manufacture and commercialize sarecycline in the greater China region. Almirall currently holds a nonexclusive license to develop and commercialize sarecycline for the treatment of rosacea in the U.S., and in the U.S., Paratek cannot grant rights on back-up compounds, lead candidate(s), or products licensed to Almirall for rosacea. The Almirall Collaboration Agreement contains two performance obligations: (i) an exclusive license to research, develop and commercialize tetracycline products for use in the U.S. for the treatment of acne and rosacea and (ii) research and development services. The performance obligation to deliver the license was satisfied upon execution of the Almirall Collaboration Agreement in July 2007. All research and development services were completed by December 2010. The options provided to Almirall for additional development services do not provide Almirall with a material right as these services will not be provided at a significant or incremental discount. As such, the option services are not performance obligations. As the performance obligation to deliver the license was satisfied in 2007 and research and development services were completed by December 2010, all subsequent milestone payments are recognized as revenue when the risk of significant reversal is resolved, generally when the milestone event occurs. The Company received an upfront fee in the amount of $4.0 million upon the execution of the Almirall Collaboration Agreement, $1.0 million upon filing of an Investigational New Drug Application in 2010, $2.5 million upon initiation of Phase 2 trials in 2012 and $4.0 million upon initiation of Phase 3 trials associated with the Almirall Collaboration Agreement in December 2014. In December 2017, the FDA’s acceptance of the NDA for sarecycline was received, triggering a milestone payment of $5.0 million earned upon acceptance of an NDA for a product licensed under the Almirall Collaboration Agreement. In October 2018, the FDA’s regulatory approval of sarecycline, under the tradename SEYSARA, triggered the last milestone payment under the Almirall Collaboration Agreement of $12.0 million. Since FDA approval of SEYSARA was outside of the Company’s control and not obtained until October 2, 2018, the achievement of the milestone was not deemed probable and the risk of significant reversal of revenue was not resolved until such time. Upon the FDA approval, the uncertainty related to this milestone was resolved and a significant reversal of revenue would not occur in future periods. As such, the $12.0 million milestone payment was recognized as revenue at the time of FDA approval in the fourth quarter of 2018. Almirall is also obligated to pay the Company tiered royalties, ranging from the mid-single digits to the low double digits, based on net sales of tetracycline compounds developed under the Almirall Collaboration Agreement, with a standard royalty reduction post patent expiration for such product for the remainder of the royalty term. Almirall’s obligation to pay the Company royalties for each tetracycline compound it commercializes under the Almirall Collaboration Agreement expires on the later of the expiration of the last to expire patent that covers the tetracycline compound in the U.S. and the date on which generic drugs that compete with the tetracycline compound reach a certain threshold market share in the U.S. Royalty payments are recognized when the sales occur. The Company recognized $0.2 million of royalty revenue recognized for sales of SEYSARA in the U.S. by Almirall for the three months ended March 31, 2020 under the Almirall Collaboration Agreement. During the first quarter of 2020, royalty revenue recognized for sales of SEYSARA in the U.S. was estimated using third party data and an approximation of discounts and allowances to calculate net product sales, to which the Company then applied the applicable royalty percentage specified in the Almirall Collaboration Agreement. Differences between actual and estimated royalty revenues will be adjusted for in the period in which they become known, which is expected to be the following quarter. During the three months ended March 31, 2020, the Company recorded an adjustment of $0.1 million to decrease the estimated royalty revenue to the actual royalty revenue payment received for sales that occurred during the three months ended December 31, 2019 In February 2020, the Company entered into (i) an ex-U.S. license agreement with Almirall, or the Ex-U.S. License, under which Almirall granted the Company an exclusive license in and to certain technology owned or in-licensed by Almirall or its affiliates in order to research, develop, manufacture and commercialize sarecycline for the treatment of acne in all countries other than the U.S. and (ii) a license agreement with Almirall that is specific to China, or the China License, under which the Company granted to Almirall an exclusive license in and to certain technology owned or in-licensed by the Company or its affiliates in order to research, develop and commercialize sarecycline for the treatment of acne in the greater China region. Under the terms of the China License, Almirall is responsible for and is obligated to use commercially reasonable efforts to develop and commercialize sarecycline for the treatment of acne, including requirements to (i) file an Investigational New Drug Application (or analogous foreign submission) for sarecycline for the treatment of acne in the greater China region in calendar year 2020, (ii) receive regulatory approval for sarecycline for the treatment of acne in the greater China region within seven years following such submission and (iii) commercialize sarecycline for the treatment of acne in the greater China region within eighteen months after obtaining regulatory approval. If Almirall does not satisfy the diligence requirements set forth in subclauses (ii) or (iii) above, the Company may terminate the China License. The Company has agreed during the term of the Ex-U.S. License to use commercially reasonable efforts to not, directly or indirectly, make sarecycline products commercialized by the Company, its affiliates or its sublicensees available for resale in the U.S., and Almirall has agreed during the term of the Ex-U.S. License to use commercially reasonable efforts to not, directly or indirectly, make sarecycline products commercialized by Almirall, their affiliates or their sublicensees available for resale outside of the greater China region. Similarly, the Company has agreed during the term of the China License to use commercially reasonable efforts to not, directly or indirectly, make sarecycline products commercialized by the Company, its affiliates or its sublicensees available for resale in the greater China region, and Almirall has agreed during the term of the China License to use commercially reasonable efforts to not, directly or indirectly, make sarecycline products commercialized by Almirall, their affiliates or their sublicensees available for resale outside of the greater China region, other than as provided in the Almirall Collaboration Agreement. In connection with the Ex-U.S. License, the Company pays Almirall, on a country-by-country and product-by-product basis, (i) for eight years following the first commercial sale of a sarecycline product in a country, a royalty in the middle-single digits on its or its affiliates’ nets sales of sarecycline products outside of the U.S., subject to certain standard reductions, and (ii) for fifteen years following the first commercial sale of a sarecycline product in a country, a percentage of the consideration (e.g., milestones, royalties) we receive from sublicensees in connection with developing and commercializing sarecycline outside of the U.S., which ranges from one-fifth to one-half of such consideration, subject to certain standard reductions. In connection with the China License, for fifteen years following the first commercial sale of a sarecycline product in China, Almirall pays the Company a royalty in the high-single digits on their, their affiliates’ or their sublicensees’ net sales of sarecycline products in the greater China region, subject to certain standard reductions. Tufts University In February 1997, the Company and Tufts University, or Tufts, entered into a license agreement under which the Company acquired an exclusive license to certain patent applications and other intellectual property of Tufts related to the drug resistance field to develop and commercialize products for the treatment or prevention of bacterial or microbial diseases or medical conditions in humans or animals or for agriculture. The Company subsequently entered into eleven amendments to that agreement, collectively the Tufts License Agreement, to include patent applications filed after the effective date of the original license agreement, to exclusively license additional technology from Tufts, to expand the field of the agreement to include disinfectant applications, and to change the royalty rate and percentage of sublicense income paid by the Company to Tufts under sublicense agreements with specified sublicensees. The Company is obligated under the Tufts License Agreement to provide Tufts with annual diligence reports and a business plan and to meet certain other diligence milestones. The Company has the right to grant sublicenses of the licensed rights to third parties, which will be subject to the prior approval of Tufts unless the proposed sublicensee meets a certain net worth or market capitalization threshold. The Company is primarily responsible for the preparation, filing, prosecution and maintenance of all patent applications and patents covering the intellectual property licensed under the Tufts License Agreement at its sole expense. The Company has the first right, but not the obligation, to enforce the licensed intellectual property against infringement by third parties. The Company issued Tufts 1,024 shares of the Company’s common stock on the date of execution of the original license agreement, and the Company was required to make certain payments of up to $0.3 million to Tufts upon the achievement by products developed under the Tufts License Agreement of specified development and regulatory approval milestones. The Company made a payment of $50,000 to Tufts for achieving the first milestone following commencement of the Phase 3 clinical trial for omadacycline and a payment of $100,000 to Tufts for achieving the second milestone following its first marketing application submitted in the U.S. The third, and final, payment of $150,000 became due upon FDA approval of omadacycline in October 2018. The Company is also obligated to pay Tufts a minimum royalty payment in the amount of $25,000 per year. In addition, the Company is obligated to pay Tufts royalties based on gross sales of products, as defined in the agreement, ranging in the low single digits depending on the applicable field of use for such product sale. If the Company enters into a sublicense under the Tufts License Agreement, based on the applicable field of use for such product, the Company will be obligated to pay Tufts (i) a percentage, ranging from 10% to 14% (ten percent to fourteen percent) for compounds other than omadacycline, and a percentage in the single digits for the compound omadacycline, of that portion of any sublicense issue fees or maintenance fees received by the Company that are reasonably attributable to the sublicense of the rights granted to the Company under the Tufts License Agreement and (ii) the lesser of (a) a percentage, ranging from the low tens to the high twenties based on the applicable field of use for such product, of the royalty payments made to the Company by the sublicensee or (b) the amount of royalty payments that would have been paid by the Company to Tufts if the Company had sold the product. Unless terminated earlier, the Tufts License Agreement will expire at the same time as the last-to-expire patent in the patent rights licensed to the Company under the agreement and after any such expiration the Company will continue to have an exclusive, fully-paid-up license to such intellectual property licensed from Tufts. Tufts has the right to terminate the agreement upon 30 days’ notice should the Company fail to make a material payment under the Tufts License Agreement or commit a material breach of the agreement and not cure such failure or breach within such 30-day period, or if, after the Company has started to commercialize a product under the Tufts License Agreement, the Company ceases to carry on its business for a period of 90 consecutive days. The Company has the right to terminate the Tufts License Agreement at any time upon 180 days’ notice. Tufts has the right to convert the Company’s exclusive license to a non-exclusive license if the Company does not commercialize a product licensed under the Tufts License Agreement within a specified time period. The Company incurred $0.1 million and an insignificant amount of royalty expense for the three months ended March 31, 2020 and March 31, 2019, respectively. Past Collaborations Novartis International Pharmaceutical Ltd. In September 2009, the Company and Novartis International Pharmaceutical Ltd., or Novartis, entered into a Collaborative Development, Manufacture and Commercialization License Agreement, or the Novartis Agreement, which provided Novartis with a global, exclusive patent and technology license for the development, manufacturing and marketing of omadacycline. The Novartis Agreement was terminated by Novartis without cause in June 2011 and the termination was effective 60 days later. The Company and Novartis subsequently entered in a letter agreement in January 2012, or the Novartis Letter Agreement, as amended, pursuant to which we reconciled shared development costs and expenses and granted Novartis a right of first negotiation with respect to commercialization rights of omadacycline following approval of omadacycline from the FDA, European Medicines Agency, or any regulatory agency, but only to the extent the Company had not previously granted such commercialization rights related to omadacycline to another third party as of any such approval. The Company also agreed to pay Novartis a 0.25% royalty, to be paid from net sales received by the Company in any country following the launch of omadacycline in that country and continuing until the later of expiration of the last active valid patent claim covering such product in the country of sale and 10 years from the date of first commercial sale in such country. The first royalty payment became payable as of March 31, 2019. The amended Novartis Letter Agreement resulted in a long-term liability in the amount of $3.4 million and $3.4 million as of March 31, 2020 and December 31, 2019, respectively, included within “Other liabilities” on the Company’s consolidated balance sheet. In addition, a short-term liability of $0.1 million, included within “Other current liabilities” on the Company’s consolidated balance sheet, exists as of March 31, 2020 that represents the portion of royalty payments due to Novartis within twelve months. There are no other payment obligations to Novartis under the Novartis Agreement or the amended Novartis Letter Agreement.

Capital Stock

Capital Stock	3 Months Ended
	Mar. 31, 2020
Equity [Abstract]
Capital Stock	9. Capital Stock I n July 2019, the Company entered into an At the Market Sales Agreement, or the 2019 Sales Agreement, with Jefferies LLC, or Jefferies, and BTIG, LLC, or BTIG, under which it may offer and sell its common stock having aggregate sales proceeds of up to $50.0 million from time to time through Jefferies or BTIG as its sales agents. Sales of the Company’s common stock through Jefferies or BTIG, if any, will be made by any method permitted by law deemed to be an “at the market offering” as defined in Rule 415(a)(4) under the Securities Act of 1933, as amended, including without limitation sales made directly on the Nasdaq Global Market or any other existing trading market for its common stock. Jefferies and BTIG will use commercially reasonable efforts to sell the Company’s common stock from time to time, based upon instructions from the Company (including any price, time or size limits or other customary parameters or conditions we may impose). The Company will pay Jefferies or BTIG, as applicable, a commission of 3% of the gross sales proceeds of any common stock sold through Jefferies and BTIG under the 2019 Sales Agreement. The Company has also provided Jefferies and BTIG with customary indemnification rights. The Company is not obligated to make any sales of common stock under the 2019 Sales Agreement. The Company sold 2,334,107 shares of common stock pursuant to the 2019 Sales Agreement for $9.1 million in proceeds, after deducting commissions of $0.3 million, during the three months ended March 31, 2020. The offering of shares of the Company’s common stock pursuant to the 2019 Sales Agreement will terminate upon the earlier of (i) the sale of all common stock subject to the 2019 Sales Agreement, or (ii) termination of the 2019 Sales Agreement in accordance with its terms. Warrants to Purchase Common Stock Warrants to purchase preferred stock with intrinsic value issued to HBM Healthcare Investments (Cayman) Ltd., Omega Fund III, L.P., and K/S Danish BioVenture, all beneficial owners of more than 5% of the Company’s common stock, were exchanged for 9,614 warrants to purchase common stock in connection with the with the business combination between privately-held Paratek Pharmaceuticals, Inc. and Transcept Pharmaceuticals, Inc. in October 2014, or the will, if not exercised, In connection with the Loan and Security Agreement, dated September 30, 2015, as amended from time to time, or the Hercules Loan Agreement, into which the Company entered with Hercules Technology II, L.P. and Hercules Technology III, L.P., together, Hercules, and certain other lenders and Hercules Technology Growth Capital, Inc. (as agent), the Company issued to each of Hercules Technology II, L.P. and Hercules Technology III, L.P. a warrant to purchase 16,346 shares of its common stock (32,692 shares of common stock in total) at an exercise price of $24.47 per share, or the Hercules Warrants, on September 30, 2015, which expire five years from issuance or at the consummation of a Public Acquisition, as defined in each of the Hercules Warrant agreements. In connection with the second amendment to the Hercules Loan Agreement on December 12, 2016, the Company issued to each of Hercules Technology II, L.P. and Hercules Technology III, L.P. a warrant to purchase 18,574 shares of its common stock (37,148 shares of common stock in total) at an exercise price of $13.46 per share, or the Second Amendment Warrants. In connection with the borrowing under the Hercules Loan Agreement on June 27, 2017, the Company issued an additional warrant to Hercules Capital, Inc. to purchase 5,374 shares of its common stock at an exercise price of $23.26 per share, or the Additional Warrant. In connection with the fifth amendment to the Hercules Loan Agreement, on August 1, 2018, the Company issued to Hercules Capital, Inc. a warrant to purchase up to 19,627 shares of its common stock at an exercise price of $10.19 per share, or the Fifth Amendment Warrant. The Hercules Warrants, Second Amendment Warrants, Additional Warrant and the Fifth Amendment Warrant, collectively referred to as the Warrants, may be exercised on a cashless basis. The Warrants are exercisable for a term beginning on the date of issuance and ending on the earlier to occur of five years (or seven years, in the case of the Fifth Amendment Warrant) from the date of issuance or the consummation of certain acquisitions of the Company as set forth in the various agreements for the Warrants.

Accrued Expenses

Accrued Expenses	3 Months Ended
	Mar. 31, 2020
Payables And Accruals [Abstract]
Accounts Expenses	10. Accrued Expenses Accrued expenses consist of the following (in thousands): March 31, December 31, 2020 2019 Accrued interest $ 4,221 $ 2,264 Accrued compensation 3,632 7,580 Accrued sales allowances 2,188 1,492 Accrued commercial 1,874 1,445 Accrued inventory 1,756 125 Accrued manufacturing 1,713 1,026 Accrued contract research 1,226 1,612 Accrued professional fees 968 876 Accrued legal costs 394 181 Accrued other 128 95 Total $ 18,100 $ 16,696

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	11. Fair Value Measurements Financial instruments, including cash, cash equivalents, restricted cash, money market funds, U.S. treasury securities, accounts receivable, accounts payable, and accrued expenses are carried on the condensed consolidated financial statements at amounts that approximate fair value. The fair value of the Company’s long-term debt is determined using current applicable rates for similar instruments as of the balance sheet date. The fair value of the Company’s debt (including the Notes as defined in Note 13, Long-Term Debt) The following table presents information about the Company’s financial assets and liabilities that have been measured at fair value as of March 31, 2020 and December 31, 2019 and indicate the fair value hierarchy of the valuation inputs utilized to determine such fair value. In general, fair values determined by Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets or liabilities. Fair values determined by Level 2 inputs utilize observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities or other inputs that are observable market data. Fair values determined by Level 3 inputs utilize unobservable data points for the asset or liability, and include situations where there is little, if any, market activity for the asset or liability (in thousands): Description Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total March 31, 2020 Assets: U.S. treasury securities $ 70,166 $ — $ — $ 70,166 Total Assets $ 70,166 $ — $ — $ 70,166 December 31, 2019 Assets: U.S. treasury securities $ 113,077 $ — $ — $ 113,077 Total Assets $ 113,077 $ — $ — $ 113,077 Marketable Securities U.S. treasury securities fair values can be obtained through quoted market prices in active exchange markets and are therefore classified as Level 1.

Stock-Based and Incentive Compe

Stock-Based and Incentive Compensation	3 Months Ended
	Mar. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based and Incentive Compensation	12. Stock-Based and Incentive Compensation Stock-based Compensation The following table presents stock-based compensation expense included in the Company’s condensed consolidated statements of operations and comprehensive loss (in thousands): Three Months Ended March 31, 2020 2019 Research and development expense $ 587 $ 1,435 Selling, general and administrative expense 1,948 2,428 Total stock-based compensation expense $ 2,535 $ 3,863 Stock-based compensation expense is estimated as of the grant date based on the fair value of the award and is recognized as expense over the requisite service period, which generally represents the vesting period. The Company estimates the fair value of its stock options using the Black-Scholes option-pricing model. The weighted-average assumptions used to determine the fair value of the stock option grants is as follows: Three Months Ended March 31, 2020 2019 Volatility 61.9 % 64.8 % Risk-free interest rate 1.3 % 2.5 % Expected dividend yield 0.0 % 0.0 % Expected life of options (in years) 5.6 5.6 Stock Option Plan Activity The Company’s Board of Directors adopted the Paratek Pharmaceuticals, Inc. 2015 Equity Incentive Plan, or the 2015 Plan, which was approved by Company stockholders at the annual meeting of shareholders held on June 9, 2015, reserving 1,200,000 shares of common stock for the grant of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock awards, RSU awards, performance stock awards, performance cash awards and other stock awards to directors, officers, employees and consultants. The 2015 Plan is intended to be the successor to and continuation of the Paratek Pharmaceuticals, Inc., 2006 Incentive Award Plan and the Paratek Pharmaceuticals, Inc. 2014 Equity Incentive Plan, or collectively, the Prior Plans. When the 2015 Plan became effective, no additional stock awards were granted under the Prior Plans, although all outstanding stock awards granted under the Prior Plans will continue to be subject to the terms and conditions as set forth in the agreements evidencing such stock awards and the terms of the Prior Plans. On January 1, 2020, 1,991,387 shares of common stock were automatically added to the shares authorized for issuance under the 2015 Plan pursuant to a “Share Reserve” provision contained in the 2015 Plan. The Share Reserve automatically increases on January 1 of each year, for the period commencing on (and including) January 1, 2016 and ending on (and including) January 1, 2025, in an amount equal to 5% of the total number of shares of common stock outstanding on December 31 of the preceding calendar year. Notwithstanding the foregoing, the Board of Directors of the Company may act prior to January 1 of a given year to provide that there will be no January 1 increase in the Share Reserve for such year or that the increase in the Share Reserve for such year will be a lesser number of shares of common stock than would otherwise automatically occur. Total shares available for future issuance under the 2015 Plan are 82,749 shares as of March 31, 2020. The Company recognizes the stock-based compensation expense stock-based compensation expense stock-based compensation expense During the three months ended March 31, 2020, the Company’s Board of Directors granted 61,300 stock options and 2,495,950 RSUs to directors, executives and employees of the Company under the 2015 Plan. The stock option awards are subject to time-based vesting over a period of one to four years. The RSU awards granted to executives in February 2020 are subject to time-based vesting, with 1/3 of the shares vesting on December 10, 2020, or the Initial Vest Date, and an additional 1/3 of the shares vesting on the succeeding two anniversaries of the Initial Vesting Date. The RSU awards granted to non-executive employees of the Company in February 2020 are subject to time-based vesting and vest in three equal installments commencing on each of the one-year anniversaries of the grant date. The grants also included performance-based RSU, or PRSU, awards to certain executives and employees of the Company. The PRSU awards granted in February 2020 will vest as follows: (a) 25/55 on certain net product revenue achievements, (b) 15/55 on achievement of certain clinical milestones related to NUZYRA and (c) 15/55 on achievement of certain regulatory milestones related to NUZYRA. No stock-based compensation expense has been recognized related to the milestones above as the Company does not deem the achievement of the events to be probable as of March 31, 2020. During the year ended December 31, 2019, the Company’s Board of Directors granted PRSU awards to certain executives and employees of the Company in February 2019 and July 2019 under the 2015 Plan that will vest as follows: (a) 25/60 and (b) 25/60, each, on certain net product revenue achievements and (c) the remaining 10/60 on certain other business achievements. Since the Company believes it is probable that milestones (a) and (b) above will be achieved, the Company recognized stock-based compensation expense for a total of $0.4 million for the performance conditions during the three months ended March 31, 2020 using the accelerated attribution method. During the three months ended March 31, 2020, the Company’s Board of Directors modified the vesting terms related to the PRSUs that were expected to time vest on attainment of certain other business achievements. The modification resulted in the recognition of an insignificant amount of stock-based compensation expense during the three months ended March 31, 2020. During the year ended December 31, 2018, the Company’s Board of Directors granted PRSU awards to certain executives and employees of the Company and those awards have vested or will vest as follows: (a) 10/55 shall be earned and time vest on achievement of European Medicines Agency, or EMA, filing preliminary validation, which occurred in October 2018, (b) 20/55 shall be earned and time vest on achievement of EMA approval of omadacycline, and (c) 25/55 shall be earned on achievement of the launch of omadacycline in the U.S. and time vest on the date that is 15 months following such launch date. During the year ended December 31, 2019, the Company’s Board of Directors modified the vesting terms related to the PRSUs in (b) above which were expected to time vest on achievement of EMA approval . The Company determined the awards were probable of vesting under the modified conditions. The modification resulted in 136,000 shares vesting during the year ended December 31, 2019 and the recognition of of $0.5 million during the year ended December 31, 2019. The Company’s Board of Directors adopted the Paratek Pharmaceuticals, Inc. 2015 Inducement Plan, or the 2015 Inducement Plan, in accordance with Nasdaq Rule 5635(c)(4), reserving 360,000 shares of common stock solely for the grant of inducement stock options 306,500 In June 2017, the Company’s Board of Directors adopted the Paratek Pharmaceuticals, Inc. 2017 Inducement Plan, or the 2017 Inducement Plan, in accordance with Nasdaq Rule 5635(c)(4), reserving 550,000 shares of common stock solely for the grant of inducement stock options and RSU awards to employees entering into employment or returning to employment after a bona fide period of non-employment with the Company. In October 2018, the Company’s Board of Directors approved the reserve of an additional 500,000 shares for the 2017 Inducement Plan, for a total of 1,050,000 shares reserved for issuance under it. During the three months ended March 31, 2020, the Company’s Board of Directors granted 21,100 stock options and 17,600 RSUs to employees of the Company under the 2017 Inducement Plan. The stock option awards are subject to time-based vesting over a period of one to four years. The RSU awards are generally subject to time-based vesting, with 100% of the shares of common stock subject to the RSU award vesting three years from the grant date. As of March 31, 2020, 379,666 shares remain available for grant under the 2017 Inducement Plan, as well as any shares underlying awards that may become available for grant pursuant to the plan’s terms. Stock Options A summary of stock option activity for the three months ended March 31, 2020 is as follows: Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Outstanding at December 31, 2019 3,236,073 $ 15.54 6.30 $ 90 Granted 82,400 Cancelled or forfeited (8,573 ) Outstanding at March 31, 2020 3,309,900 $ 15.25 5.87 $ 1 Exercisable at March 31, 2020 2,877,454 $ 16.05 5.45 $ — In April 2020, certain executives voluntarily forfeited 1,073,891 outstanding stock options with exercise prices significantly above the current trading price of the Company’s common stock in order to make additional shares available for future grants to Company employees subsequent to the quarter ended March 31, 2020 under the Company’s 2014 Equity Incentive Plan, 2015 Equity Incentive Plan, and the 2017 Inducement Plan. The Company recognizes the effect of forfeitures as stock-based compensation expense as they occur. Restricted Stock Units A summary of RSU activity for the three months ended March 31, 2020 is as follows: Number of Shares Weighted Average Grant Date Fair Value Unvested balance at December 31, 2019 2,305,408 $ 7.66 Granted 2,513,550 3.52 Released (252,670 ) 8.42 Forfeited (121,834 ) 9.50 Unvested balance at March 31, 2020 4,444,454 $ 5.22 Total unrecognized stock-based compensation expense for all stock-based awards was $14.0 million as of March 31, 2020. This amount will be recognized over a weighted-average period of 1.78 years. 2009 Employee Stock Purchase Plan On June 3, 2009, at the annual meeting of stockholders, the stockholders of the Company approved the 2009 Employee Stock Purchase Plan, or the 2009 ESPP. The Company’s 2009 ESPP is designed to allow eligible employees of the Company to purchase shares of common stock through periodic payroll deductions and during specified offering periods under the plan. The price of common stock purchased under the 2009 ESPP is equal to 85% of the lower of the fair market value of the common stock on the commencement date of each offering period or the specified purchase date. As of March 31, 2020, 36,539 shares were available for issuance under the 2009 ESPP. Since the Merger, the Company has not made the 2009 ESPP available to employees. 2018 Employee Stock Purchase Plan The Company’s Board of Directors adopted, and in June 2018 Company’s stockholders approved, the Paratek Pharmaceuticals, Inc. 2018 Employee Stock Purchase Plan, or the 2018 ESPP. The 2018 ESPP was amended in October 2018 to change the commencement dates of the offering periods. The maximum aggregate number of shares of the Company’s common stock that may be purchased under the 2018 ESPP is 943,294 shares, or the ESPP Share Pool, subject to adjustment as provided for in the 2018 ESPP. The 2018 ESPP allows eligible employees to purchase shares during certain offering periods, which will be six -month periods commencing June 1 and ending November 30 and commencing December 1 and ending May 31 of each year As of March 31, 2020, 761,648 shares remain available for issuance. During the three months ended March 31, 2020, the Company recognized an insignificant amount in related stock-based compensation expense. Revenue Performance Incentive Plan On October 4, 2018, the Company adopted the Revenue Performance Incentive Plan, or the Plan, to grant performance-based cash incentive awards to key employees and consultants of the Company. The Plan provides for an incentive pool of up to $50.0 million, plus accrued interest during the period between the awards’ vesting date and payment dates. Each participant will be allocated a percentage of the incentive pool. The incentive pool will be divided into two equal tranches with the first tranche vesting upon the Company’s achievement of cumulative net product revenues over $300.0 million by December 31, 2025, or Tranche 1, and the second tranche vesting upon the Company’s achievement of cumulative product revenues over $600.0 million by December 31, 2026, or Tranche 2. Participants will vest annually in each tranche of their awards in four equal installments on December 31, 2019, December 31, 2020, December 31, 2021, and December 31, 2022, subject to their continued employment with the Company through the applicable vesting date. If a participant’s employment terminates prior to December 31, 2022 due to death or disability, the participant will automatically vest in an additional 25% of each tranche of his or her award. Upon the achievement of a Tranche 1 or Tranche 2 milestone (but not a deemed achievement in connection with a change of control), each participant who has remained in continuous employment with the Company through December 31, 2022 will be 100% vested in the applicable tranche. In the event of a change of control of the Company prior to December 31, 2026, participants whose employment has terminated prior to such date will be eligible for payouts under the Plan based on the then-vested portion of their awards, and participants who have remained employed through the change of control will be deemed to have time vested in full in each tranche of their awards. Upon the achievement of a Tranche 1 or Tranche 2 milestone (but not a deemed achievement in connection with a change of control), each participant’s payout in respect of the applicable tranche of his or her award will equal (a) the participant’s then-vested percentage, multiplied by (b) $25 million, multiplied by (c) the participant’s individual percentage allocation of the incentive pool. If a change of control occurs prior to December 31, 2026, and the Tranche 1 milestone was not achieved prior to the change of control, the Tranche 1 milestone will be deemed to be achieved at a percentage equal to the greater of (1) 50% and (2) the cumulative product revenues as of the change of control, divided by $300.0 million. If a change of control occurs prior to December 31, 2026, and the Tranche 2 milestone was not achieved prior to the change of control, the Tranche 2 milestone will be deemed to be achieved at a percentage equal to the greater of (1) 30% and (2) the cumulative product revenues as of the change of control, divided by $600.0 million. A participant’s payout in respect of each tranche of his or her award in a change of control will equal (1) the participant’s then-vested percentage of such tranche, multiplied by (2) the percentage of that tranche’s milestone that has been achieved or is deemed to have been achieved, multiplied by (3) $25.0 million, multiplied by (4) the participant’s individual percentage allocation of the incentive pool. Amounts that become payable upon achievement of the Tranche 1 milestone will be paid in a lump-sum in the first quarter of 2026 and amounts that become payable upon achievement of the Tranche 2 milestone will be paid in a lump-sum in the first quarter of 2027. In the event of a change of control, any portion of the incentive pool that is earned, but unpaid, or deemed earned in connection with the change of control will be paid at the time of the change of control. If a change of control occurs prior to the achievement of either or both of the Tranche 1 and Tranche 2 milestones, the awards will remain outstanding and the remaining unpaid portion of the incentive pool applicable to the Tranche 1 or Tranche 2 milestone, as applicable, will be paid following the achievement of either such milestone at the time or times the bonuses would otherwise be paid out. Any successor in interest to the Company upon or following a change of control will be required to assume all obligations under the Plan. Awards may be paid out in cash or in a combination of cash and registered securities of equal value (based on the Company’s 20-day trailing average closing common stock price), with the portion paid in registered securities not to exceed 50% of the aggregate payment amount with respect to each tranche; provided, however, that any amounts payable with respect to an award in connection with a change in control will be paid in cash. The Company will recognize the compensation cost over the requisite service period, to the extent achievement of the performance condition is deemed probable relative to targeted performance. The performance condition is not yet deemed probable; as such, no amounts were accrued under the Plan during the three months ended March 31, 2020.

Long-Term Debt

Long-Term Debt	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Long-Term Debt	13. Long-Term Debt Hercules Loan Agreement On June 27, 2019, the Company entered into an Amended and Restated Loan and Security Agreement, or the Loan Agreement, with Hercules Technology III, L.P., certain other lenders, together, the Lenders, and Hercules Capital, Inc. (as agent), under which the Company may borrow up to $100.0 million in multiple tranches, each, a Term Loan Tranche. The Loan Agreement amends and restates in its entirety the Company’s prior Loan and Security Agreement with the Lenders dated as of September 30, 2015 to, among other things, provide for an extension of the scheduled maturity date of the $60.0 million Term Loan Tranche, or the First Tranche, from September 1, 2021 to September 1, 2023, upon certain events set forth in the Loan Agreement, and an extension of the scheduled maturity date of the $10.0 million Term Loan Tranche, or the Second Tranche, and additional Term Loan Tranches (if any), from August 1, 2022 to August 1, 2024, upon certain events set forth in the Loan Agreement. The Loan Agreement also provides for an additional $10.0 million of additional Term Loan Tranches (up to a total of $30.0 million of additional Term Loan Tranches) that may be available to the Company, subject to approval by Hercules, in its sole discretion, whether to provide such tranches. As such there can be no assurance as to whether or not the additional Term Loan Tranches shall be funded. The interest rate with respect to the First Tranche is a floating per annum rate equal to the greater of (i) 8.50% plus the prime rate as reported from time to time in The Wall Street Journal minus 5.75%, and (ii) 8.50%. The interest rate with respect to the Second Tranche is, and the interest rate with respect to additional Term Loan Tranches (if any) will be, a floating per annum rate equal to the greater of (i) 7.85% plus the prime rate as reported from time to time in The Wall Street Journal minus 5.75%, and (ii) 7.85%. An end of term charge equal to 4.5% with respect to $50.0 million of the First Tranche and equal to 2.25% with respect to the remaining $10.0 million of the First Tranche of the issued principal balance of the term loans is payable in September of 2020, and an end of term charge equal to 6.95% of the Second Tranche, and the Additional Term Loan Tranches (if any), of the issued principal balance of the term loans is payable at maturity, including in the event of any prepayment, and is being accrued as interest expense over the term of the term loans using the effective interest method. Payments under the Loan Agreement with respect to the First Tranche are interest only until January 1, 2021, followed by equal monthly payments of principal and interest through the scheduled maturity date. Payments under the Loan Agreement with respect to the Second Tranche are, and with respect to additional Term Loan Tranches (if any) will be, interest only until January 1, 2021 (which can be extended to May 1, 2021 or September 1, 2021, upon certain events set forth in the Loan Agreement), followed by equal monthly payments of principal and interest through the scheduled maturity date. The Company’s obligations under the Loan Agreement are secured by a security interest in substantially all of its and Paratek Pharma, LLC’s assets, other than intellectual property. Under the Amended and Restated Loan Agreement, prepayment fees equaling 1.0% to 2.5% will apply to principal amounts prepaid prior to dates between September 1, 2020 and January 1, 2021, varying depending on the applicable tranche. The Loan Agreement includes customary affirmative and restrictive covenants, including a liquidity covenant and a covenant against suffering a “change of control,” and also includes customary events of default, including payment defaults, breaches of covenants following any applicable cure period, a material impairment in the perfection or priority of Lenders’ security interest or in the value of the collateral, cross acceleration to the debt and certain events relating to bankruptcy or insolvency. Upon the occurrence of an event of default, a default interest rate of an additional 5% may be applied to the outstanding loan balances, and the Lenders may declare all outstanding obligations immediately due and payable and take such other actions as set forth in the Loan Agreement. Borrowings under the Hercules Loan Agreement are collateralized by substantially all of the assets of the Company. Upon an Event of Default, an additional 5.0% interest would be applied, and Hercules could, at its option, accelerate and demand payment of all or any part of the term loans together with the prepayment and end of term charges. An Event of Default is defined in the Hercules Loan Agreement as (i) failure to make required payments; (ii) failure to adhere to financial, operating and reporting loan covenants; (iii) an event or development occurs that would be reasonably expected to have a material adverse effect; (iv) false representations in the Hercules Loan Agreement; (v) insolvency, as described in the Hercules Loan Agreement; (vi) levy or attachments on any of the Company's assets; and (vii) default of any other agreement or subordinated debt greater than $1.0 million. In the event of insolvency, this acceleration and declaration would be automatic. In addition, in connection with the Hercules Loan Agreement, the Company agreed to provide Hercules with a contingent security interest in the Company's bank accounts. The Company's control of its bank accounts is not adversely affected unless Hercules elects to obtain unilateral control of the Company's bank accounts by declaring that an Event of Default has occurred. The principal of the term loans, which is not due within 12 months of March 31, 2020, has been classified as long-term debt. The Company recognized interest expense of $1.7 million on the Hercules Loan Agreement The following table summarizes the impact of the Hercules Loan Agreement on the Company’s consolidated balance sheets at March 31, 2020 and December 31, 2019 (in thousands): March 31, 2020 December 31, 2019 Gross proceeds $ 70,000 $ 70,000 Unamortized debt issuance costs (299 ) (361 ) Carrying value $ 69,701 $ 69,639 Debt issuance costs are presented on the consolidated balance sheet as a direct deduction from the related debt liability rather than capitalized as an asset in accordance with ASU No. 2015-03, Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs Future principal payments, which exclude the end of term charge, in connection with the Hercules Loan Agreement as of March 31, 2020 are as follows (in thousands): Fiscal Year 2020 $ — 2021 65,835 2022 4,165 2023 — 2024 and thereafter — Total $ 70,000 Convertible Senior Subordinated Notes On April 18, 2018, the Company entered into a Purchase Agreement, or the Purchase Agreement, with several initial purchasers, or the Initial Purchasers, for whom Merrill Lynch, Pierce, Fenner & Smith Incorporated The Purchase Agreement includes customary representations, warranties and covenants. Under the terms of the Purchase Agreement, the Company agreed to indemnify the Initial Purchasers against certain liabilities. In addition, J. Wood Capital Advisors LLC, the Company’s financial advisor, purchased $5.0 million aggregate principal amount of Notes in a separate, concurrent private placement on the same terms as other investors. The Notes were issued by the Company on April 23, 2018, pursuant to an Indenture, dated as of such date, or the Indenture, between the Company and U.S. Bank National Association, as trustee, or the Trustee. The Notes bear cash interest at the annual rate of 4.75%, payable on November 1 and May 1 of each year, beginning on November 1, 2018, and mature on May 1, 2024 unless earlier repurchased, redeemed or converted. The Company will settle conversions of the Notes through delivery of shares of common stock of the Company, in accordance with the terms of the Indenture. The initial conversion rate for the Notes is 62.8931 shares of common stock (subject to adjustment as provided for in the Indenture) per $1,000 principal amount of the Notes, which is equal to an initial conversion price of approximately $15.90 per share, representing a conversion premium of approximately 20% above the closing price of the common stock of $13.25 per share on April 18, 2018. Holders of the Notes may convert all or any portion of their Notes, in multiples of $1,000 principal amount, at their option at any time prior to the close of business on the second scheduled trading day immediately preceding the stated maturity date. The Company may not redeem the Notes prior to May 6, 2021. The Company may redeem for cash all or part of the Notes, at its option, on or after May 6, 2021 if the last reported sale price of the Company’s common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) ending on, and including, the trading day immediately preceding the date on which the Company provides notice of redemption at a redemption price equal to 100% of the principal amount of the Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date. If the Company experiences a fundamental change, as described in the Indenture, prior to the maturity date of the Notes, holders of the Notes will, subject to specified conditions, have the right, at their option, to require the Company to repurchase for cash all or a portion of their Notes at a repurchase price equal to 100% of the principal amount of the Notes to be repurchased, plus accrued and unpaid interest, if any, to, but not including, the fundamental change repurchase date. In addition, following certain corporate events that occur prior to the maturity date of the Notes and following a notice of redemption of the Notes, the Company will increase the conversion rate for a holder who elects to convert its Notes in connection with such corporate event or redemption. The Indenture provides for customary events of default. In the case of an event of default with respect to the Notes arising from specified events of bankruptcy or insolvency, all outstanding Notes will become due and payable immediately without further action or notice. If any other event of default with respect to the Notes under the Indenture occurs or is continuing, the Trustee or holders of at least 25% in aggregate principal amount of the then outstanding Notes may declare the principal amount of the Notes to be immediately due and payable. After deducting costs incurred of $6.0 million, t he Company raised net proceeds from the issuance of long-term convertible debt of $159.0 million in April 2018. All costs were deferred and are being amortized over the life of the Notes at an effective interest rate of 5.47% and recorded as additional interest expense. The Company has evaluated the Indenture for derivatives pursuant to ASC 815, Derivatives and Hedging The Company evaluated the conversion feature and determined it was not within the scope of ASC 815 and therefore is not required to be accounted for separately. The Company concluded that the embedded conversion option is not subject to separate accounting pursuant to either the cash conversion guidance or the beneficial conversion feature guidance. Under the general conversion guidance in ASC 470, Debt , all of the proceeds received from the Notes was recorded as a liability on the condensed consolidated balance sheet. The following table summarizes how the issuance of the Notes is reflected in the Company’s consolidated balance sheets at March 31, 2020 and December 31, 2019: March 31, 2020 December 31, 2019 Gross proceeds $ 165,000 $ 165,000 Unamortized debt issuance costs (4,298 ) (4,531 ) Carrying value $ 160,702 $ 160,469 The Company recognized coupon interest expense of $2.0 million and amortization expense on the debt issuance costs of $0.2 million on the Notes for the three months ended March 31, 2020. Royalty-Backed Loan Agreement On February 25, 2019, the Company, through its wholly-owned subsidiary Paratek Royalty Corporation, or the Subsidiary, entered into a royalty-backed loan agreement, or the Royalty-Backed Loan Agreement, with Healthcare Royalty Partners III, L.P., or HCRP. Pursuant to the terms of the Royalty-Backed Loan Agreement, upon the satisfaction of the conditions precedent set forth therein, the Subsidiary borrowed a $32.5 million loan, which was secured by, and will be repaid based upon, royalties from the Almirall Collaboration Agreement. On May 1, 2019, the Company received $27.8 million, net of $0.5 million lender discount, $ 0.2 Under the Royalty-Backed Loan Agreement, the outstanding principal balance will bear interest at an annual rate of 12.0%. Payments of interest under the Royalty-Backed Loan Agreement are made quarterly out of the Almirall Collaboration Agreement royalty payments received since the immediately preceding payment date. On each interest payment date, any royalty payments in excess of accrued interest on the loan will be used to repay the principal of the loan until the balance is fully repaid. In addition, the Subsidiary made up-front payments to HCRP of (i) a 1.5% fee and (ii) up to $300,000 for HCRP’s expenses. The Royalty-Backed Loan Agreement matures on May 1, 2029, at which time, if not earlier repaid in full, the outstanding principal amount of the loan, together with any accrued and unpaid interest, and all other obligations then outstanding, shall be due and payable in cash. The Company has entered into a Pledge and Security Agreement in favor of HCRP, pursuant to which the Subsidiary’s obligations under the Loan Agreement are secured by a pledge of all of the Company’s holdings of the Subsidiary’s capital stock. The Royalty-Backed Loan Agreement contains certain customary affirmative covenants, including those relating to: use of proceeds; maintenance of books and records; financial reporting and notification; compliance with laws; and protection of Company intellectual property. The Royalty-Backed Loan Agreement also contains certain customary negative covenants, barring the Subsidiary from: certain fundamental transactions; issuing dividends and distributions; incurring additional indebtedness outside of the ordinary course of business; engaging in any business activity other than related to the Almirall Collaboration Agreement; and permitting any additional liens on the collateral provided to HCRP under the Royalty-Backed Loan Agreement. The Royalty-Backed Loan Agreement contains customary defined events of default, upon which any outstanding principal and unpaid interest shall be immediately due and payable. These include: failure to pay any principal or interest when due; any uncured breach of a representation, warranty or covenant; any uncured failure to perform or observe covenants; any uncured cross default under a material contract; any uncured breach of the Company’s representations, warranties or covenants under its Contribution and Servicing Agreement with the Subsidiary; any termination of the Almirall Collaboration Agreement; and certain bankruptcy or insolvency events. The Company recognized interest expense of $1.0 million on the Royalty-Backed Loan for the three months ended March 31, 2020. The following table summarizes the impact of the Royalty-Backed Loan Agreement on the Company’s consolidated balance sheets at March 31, 2020 and December 31, 2019 (in thousands): March 31, 2020 December 31, 2019 Gross proceeds $ 32,500 $ 32,500 Unamortized debt issuance costs (1,853 ) (1,880 ) Carrying value $ 30,647 $ 30,620 The short-term portion of long-term debt on the Company’s consolidated balance sheet at March 31, 2020 includes the carrying value of payments due under the Hercules Loan Agreement within 12 months of March 31, 2020. Long-term debt on the Company’s consolidated balance sheets at March 31, 2020 and December 31, 2019 includes the carrying value of the Hercules Loan Agreement, the Notes and the Royalty-Backed Loan Agreement.

Leases

Leases	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Leases	14. Leases Operating Leases The Company leases its Boston, Massachusetts and King of Prussia, Pennsylvania office spaces under non-cancelable operating leases expiring in 2021 and 2024, respectively. The Company entered into the original King of Prussia and Boston leases in January 2015 and April 2015, respectively. The lease terms under the original agreements were for six and four years, respectively. Each agreement had one renewal option for an extended term, which are not included in the measurement of these leases as these options are not reasonably certain to be exercised. The King of Prussia and Boston lease terms under the original agreements began in June 2015 and July 2015, respectively. The Company executed an amended lease agreement on its Boston office space in July 2016. The amended lease agreement added 4,153 rentable square feet of office space and extended the original lease term by two years. In accordance with the amended lease agreement, the Company paid a security deposit of $0.1 million. Subsequent to the amended lease agreement, the Company records monthly lease expense of approximately $49,000 for the Boston office space. In applying the transition guidance under ASU No. 2016-02, Leases , or ASC 842 , the Company retained the classification of this lease to be operating and recorded a lease liability and a right-of-use asset on the ASC 842 effective date. The Company executed an amended lease agreement on its King of Prussia office space in October 2016. The amended lease agreement is for 19,708 rentable square feet of office space and the Company took control of this office space during the first quarter of 2017. The amended lease agreement contains rent escalation and a partial rent abatement period, which is accounted for as rent expense under the straight-line method. In applying the ASC 842 transition guidance, the Company retained the classification of this lease to be operating and recorded a lease liability and a right-of-use asset on the ASC 842 effective date. The following table contains a summary of the lease costs recognized under ASC 842 and other information pertaining to the Company’s operating leases for the three months ended March 31, 2020: For the Three Months Ended March 31, 2020 Lease cost (in thousands) Operating lease cost $ 255 Variable lease cost 36 Total lease cost $ 291 Cash paid for amounts included in the measurement of lease liabilities: $ 292 Other information Weighted average remaining lease term (in years) 3.4 Weighted average discount rate 8.75 % Future minimum operating lease obligations under non-cancelable operating leases with initial terms of more than one-year as of March 31, 2020 Maturity of lease liabilities (in thousands) As of March 31, 2020 2020 $ 885 2021 964 2022 508 2023 518 2024 396 Total lease payments $ 3,271 Less: imputed interest (449 ) Total operating lease liabilities $ 2,822 The total operating liability is presented on the Company’s condensed consolidated balance sheet based on maturity dates. $1.0 million of the total operating liabilities is classified under “other current liabilities” for the portion due within twelve months, and $1.8 million is classified under “long-term lease liability”. The Company is party to a manufacturing and services agreement for which space within the manufacturing facility will be leased. This lease has not yet commenced as of the reporting date and is not included in the maturity table above.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	15 . The Company recorded no provision for income taxes for the three months ended March 31, 2020 Deferred tax assets and deferred tax liabilities are recognized based on temporary differences between the financial reporting and tax bases of assets and liabilities using statutory rates. Management of the Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets, which are comprised principally of net operating loss carryforwards and research and development credits. Under the applicable accounting standards, management has considered the Company’s history of losses and concluded that it is more likely than not that the Company will not recognize the benefits of federal and state deferred tax assets. Accordingly, a full valuation allowance has been established against the Company’s otherwise recognizable net deferred tax assets.

Product Revenue

Product Revenue	3 Months Ended
	Mar. 31, 2020
Revenue From Contract With Customer [Abstract]
Product Revenue	16. Product Revenue To date, the Company’s only source of product revenue has been from NUZYRA product sales beginning in February 2019 when NUZYRA was launch in the U.S. The following table summarizes balances and activity in each of the product revenue allowance and reserve categories (in thousands): Chargebacks, discounts and fees Government and other rebates Returns Patient assistance Total Balance at December 31, 2019 $ 299 $ 695 $ 369 $ 129 $ 1,492 Provision related to current period sales 652 951 66 64 1,733 Adjustment related to prior period sales (18 ) 59 — — 41 Credit or payments made during the period (498 ) (521 ) — (59 ) (1,078 ) Balance at March 31, 2020 $ 435 $ 1,184 $ 435 $ 134 $ 2,188

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	17. Commitments and Contingencies In the ordinary course of business, the Company is from time to time involved in lawsuits, claims, investigations, proceedings, and threats of litigation relating to intellectual property, commercial arrangements, employment and other matters. While the outcome of these proceedings and claims cannot be predicted with certainty, as of March 31, 2020 contemplated against the Company. The Company is not a party to any material proceedings in which any director, member of executive management or affiliate of the Company is either a party adverse to the Company or the Company’s subsidiaries or has a material interest adverse to the Company or the Company’s subsidiaries.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	3 Months Ended
	Mar. 31, 2020
New Accounting Pronouncements And Changes In Accounting Principles [Abstract]
Recent Accounting Pronouncements	18. Recent Accounting Pronouncements 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. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement, In January 2017, the FASB issued ASU No. 2017-04, Simplifying the Test for Goodwill Impairment In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments , or

Summary of Significant Accoun_2

Summary of Significant Accounting Policies and Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles, or U.S. GAAP, as found in the Accounting Standards Codification, or ASC, and Accounting Standards Updates, or ASU, of the Financial Accounting Standards Board, or FASB, and pursuant to the rules and regulations of the SEC. The accompanying condensed consolidated financial statements are unaudited. The unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements as of and for the year ended December 31, 2019, and, in the opinion of management, reflect all normal recurring adjustments necessary for the fair presentation of the Company’s financial position as of March 31, 2020 and December 31, 2019, results of operations for the three month periods ended March 31, 2020 and March 31, 2019, cash flows for the three month periods ended March 31, 2020 and March 31, 2019 and changes in stockholders’ deficit for the three month periods ended March 31, 2020 and March 31, 2019. The results of operations for the interim periods are not necessarily indicative of the results of operations to be expected for the year ending December 31, 2020. These unaudited interim condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements as of and for the year ended December 31, 2019, and notes thereto, which are included in the Company’s 2019 Form 10-K.
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies As of Mach 31, 2020, the Company’s significant accounting policies and estimates, which are detailed in the Company’s 2019 Form 10-K, have not changed.
Principles of Consolidation	Principles of Consolidation The accompanying unaudited condensed consolidated financial statements include the results of operations of Paratek Pharmaceuticals, Inc. and its wholly-owned subsidiaries, Paratek Pharma, LLC, Paratek Securities Corporation, Transcept Pharma , Inc.,
Use of Estimates	Use of Estimates The preparation of the accompanying unaudited condensed consolidated financial statements, in conformity with U.S. GAAP, requires the Company to make estimates and judgments that affect the reported amounts of assets, liabilities, and expenses and the disclosure of contingent liabilities in the Company’s financial statements. On an ongoing basis, the Company evaluates its estimates and judgments, including those related to, manufacturing and clinical accruals, Changes in estimates are reflected in reported results in the period in which they become known by the Company’s management.
Segment and Geographic Information	Segment and Geographic Information Operating segments are defined as components of an enterprise engaging in business activities for which discrete financial information is available and regularly reviewed by the chief operating decision maker in deciding how to allocate resources and in assessing performance. The Company views its operations and manages its business in one operating segment.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that subject the Company to credit risk consist primarily of cash, restricted cash, and accounts receivable. The Company places its cash in an accredited financial institution and this balance is above federally insured amounts. The Company has no off-balance sheet concentrations of credit risk such as foreign currency exchange contracts, option contracts or other hedging arrangements. Accounts receivable as of March 31, 2020 represents $7.2 million due from customers on sales of NUZYRA, net of prompt payment discounts, chargebacks, rebates and certain fees, as well as a $3.0 million milestone earned during the year ended December 31, 2019, but not yet received, under the Zai Collaboration Agreement (as defined below). The balance of accounts receivable as of March 31, 2020, includes revenue earned, but not yet received, of $0.4 million of royalties on SEYSARA sales under the Almirall Collaboration Agreement (as defined below) and XERAVA TM Government, License and Collaboration Agreements

Cash and Cash Equivalents and_2

Cash and Cash Equivalents and Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2020
Cash And Cash Equivalents [Abstract]
Summary of Available for Sale Securities	The following is a summary of available-for-sale securities as of March 31, 2020 and December 31, 2019 (in thousands): Amortized Cost Unrealized Gains Unrealized Losses Fair Value March 31, 2020 U.S. treasury securities $ 69,695 $ 471 $ — $ 70,166 Total $ 69,695 $ 471 $ $ 70,166 December 31, 2019 U.S. treasury securities $ 113,003 $ 89 $ (15 ) $ 113,077 Total $ 113,003 $ 89 $ (15 ) $ 113,077

Restricted Cash (Tables)

Restricted Cash (Tables)	3 Months Ended
	Mar. 31, 2020
Restricted Cash And Investments [Abstract]
Summary of Reconciliation of Cash, Cash Equivalents, and Restricted Cash Reported Within Condensed Consolidated Statement of Cash Flows	The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the condensed consolidated statement of cash flows that sum to the total of the same such amounts shown in the condensed consolidated statement of cash flows (in thousands): March 31, 2020 March 31, 2019 Cash and cash equivalents $ 124,624 $ 81,219 Short-term restricted cash 630 266 Long-term restricted cash 2,261 250 Total cash, cash equivalents and restricted cash shown on the condensed consolidated statement of cash flows $ 127,515 $ 81,735

Inventories, Net (Tables)

Inventories, Net (Tables)	3 Months Ended
	Mar. 31, 2020
Inventory Disclosure [Abstract]
Schedule of Inventories	The following table presents inventories, net (in thousands): March 31, 2020 December 31, 2019 Work in process $ 9,598 $ 9,330 Finished goods 3,874 2,249 Total inventories, net $ 13,472 $ 11,579

Fixed Assets, Net (Tables)

Fixed Assets, Net (Tables)	3 Months Ended
	Mar. 31, 2020
Property Plant And Equipment [Abstract]
Schedule of Fixed Assets, Net	Fixed assets, net, consists of the following (in thousands): March 31, 2020 December 31, 2019 Office equipment $ 866 $ 866 Machinery and equipment 567 567 Computer equipment 412 412 Computer software 798 798 Leasehold improvements 920 920 Gross fixed assets 3,563 3,563 Less: Accumulated depreciation and amortization (2,469 ) (2,336 ) Total fixed assets, net $ 1,094 $ 1,227

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Antidilutive Shares Excluded from Computation of Diluted Net Income (Loss) Per Share	The following outstanding shares subject to stock options and restricted stock units, warrants to purchase shares of common stock, common stock issuable upon conversion of convertible debt and shares issuable under the employee stock purchase plan were antidilutive due to a net loss in the periods presented and, therefore, were excluded from the dilutive securities computation as of the three months ended March 31, 2020 and 2019 as indicated below: Three Months Ended March 31, 2020 2019 Excluded potentially dilutive securities (1) Common stock issuable under outstanding convertible notes 10,377,361 10,377,361 Shares subject to outstanding options to purchase common stock 3,309,900 3,815,951 Unvested restricted stock units 4,444,454 2,837,588 Shares subject to warrants to purchase common stock 104,455 104,455 Shares issuable under employee stock purchase plan 798,187 979,833 Totals 19,034,357 18,115,188 (1) The number of shares is based on the maximum number of shares issuable on exercise or conversion of the related securities as of March 31, 2020

Accrued Expenses (Tables)

Accrued Expenses (Tables)	3 Months Ended
	Mar. 31, 2020
Payables And Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consist of the following (in thousands): March 31, December 31, 2020 2019 Accrued interest $ 4,221 $ 2,264 Accrued compensation 3,632 7,580 Accrued sales allowances 2,188 1,492 Accrued commercial 1,874 1,445 Accrued inventory 1,756 125 Accrued manufacturing 1,713 1,026 Accrued contract research 1,226 1,612 Accrued professional fees 968 876 Accrued legal costs 394 181 Accrued other 128 95 Total $ 18,100 $ 16,696

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Liabilities Measured at Fair Value	Fair values determined by Level 2 inputs utilize observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities or other inputs that are observable market data. Fair values determined by Level 3 inputs utilize unobservable data points for the asset or liability, and include situations where there is little, if any, market activity for the asset or liability (in thousands): Description Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total March 31, 2020 Assets: U.S. treasury securities $ 70,166 $ — $ — $ 70,166 Total Assets $ 70,166 $ — $ — $ 70,166 December 31, 2019 Assets: U.S. treasury securities $ 113,077 $ — $ — $ 113,077 Total Assets $ 113,077 $ — $ — $ 113,077

Stock-Based and Incentive Com_2

Stock-Based and Incentive Compensation (Tables)	3 Months Ended
	Mar. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock-Based Compensation Expense Included in Company's Condensed Consolidated Statements of Operations and Comprehensive Loss	The following table presents stock-based compensation expense included in the Company’s condensed consolidated statements of operations and comprehensive loss (in thousands): Three Months Ended March 31, 2020 2019 Research and development expense $ 587 $ 1,435 Selling, general and administrative expense 1,948 2,428 Total stock-based compensation expense $ 2,535 $ 3,863
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions	The weighted-average assumptions used to determine the fair value of the stock option grants is as follows: Three Months Ended March 31, 2020 2019 Volatility 61.9 % 64.8 % Risk-free interest rate 1.3 % 2.5 % Expected dividend yield 0.0 % 0.0 % Expected life of options (in years) 5.6 5.6
Schedule of Share-based Compensation, Stock Options, Activity	A summary of stock option activity for the three months ended March 31, 2020 is as follows: Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Outstanding at December 31, 2019 3,236,073 $ 15.54 6.30 $ 90 Granted 82,400 Cancelled or forfeited (8,573 ) Outstanding at March 31, 2020 3,309,900 $ 15.25 5.87 $ 1 Exercisable at March 31, 2020 2,877,454 $ 16.05 5.45 $ —
Schedule of Share-based Compensation, RSU, Activity	A summary of RSU activity for the three months ended March 31, 2020 is as follows: Number of Shares Weighted Average Grant Date Fair Value Unvested balance at December 31, 2019 2,305,408 $ 7.66 Granted 2,513,550 3.52 Released (252,670 ) 8.42 Forfeited (121,834 ) 9.50 Unvested balance at March 31, 2020 4,444,454 $ 5.22

Long-Term Debt (Tables)

Long-Term Debt (Tables)	3 Months Ended
	Mar. 31, 2020
Schedule of Future Principal Payments	Future principal payments, which exclude the end of term charge, in connection with the Hercules Loan Agreement as of March 31, 2020 are as follows (in thousands): Fiscal Year 2020 $ — 2021 65,835 2022 4,165 2023 — 2024 and thereafter — Total $ 70,000
Royalty Backed Loan Agreement [Member]
Summary of Debt	The following table summarizes the impact of the Royalty-Backed Loan Agreement on the Company’s consolidated balance sheets at March 31, 2020 and December 31, 2019 (in thousands): March 31, 2020 December 31, 2019 Gross proceeds $ 32,500 $ 32,500 Unamortized debt issuance costs (1,853 ) (1,880 ) Carrying value $ 30,647 $ 30,620
4.75% Convertible Senior Subordinated Notes due 2024 [Member]
Summary of Debt	The following table summarizes how the issuance of the Notes is reflected in the Company’s consolidated balance sheets at March 31, 2020 and December 31, 2019: March 31, 2020 December 31, 2019 Gross proceeds $ 165,000 $ 165,000 Unamortized debt issuance costs (4,298 ) (4,531 ) Carrying value $ 160,702 $ 160,469
Hercules Term Loan [Member]
Summary of Debt	The following table summarizes the impact of the Hercules Loan Agreement on the Company’s consolidated balance sheets at March 31, 2020 and December 31, 2019 (in thousands): March 31, 2020 December 31, 2019 Gross proceeds $ 70,000 $ 70,000 Unamortized debt issuance costs (299 ) (361 ) Carrying value $ 69,701 $ 69,639

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Summary of Lease Costs Recognized Under Topic 842 and Other Information	The following table contains a summary of the lease costs recognized under ASC 842 and other information pertaining to the Company’s operating leases for the three months ended March 31, 2020: For the Three Months Ended March 31, 2020 Lease cost (in thousands) Operating lease cost $ 255 Variable lease cost 36 Total lease cost $ 291 Cash paid for amounts included in the measurement of lease liabilities: $ 292 Other information Weighted average remaining lease term (in years) 3.4 Weighted average discount rate 8.75 %
Summary of Future Minimum Operating Lease Obligations under Non-cancelable Operating Leases	Future minimum operating lease obligations under non-cancelable operating leases with initial terms of more than one-year as of March 31, 2020 Maturity of lease liabilities (in thousands) As of March 31, 2020 2020 $ 885 2021 964 2022 508 2023 518 2024 396 Total lease payments $ 3,271 Less: imputed interest (449 ) Total operating lease liabilities $ 2,822

Product Revenue (Tables)

Product Revenue (Tables)	3 Months Ended
	Mar. 31, 2020
Revenue From Contract With Customer [Abstract]
Schedule Of Product Revenue Allowance And Reserve Categories	The following table summarizes balances and activity in each of the product revenue allowance and reserve categories (in thousands): Chargebacks, discounts and fees Government and other rebates Returns Patient assistance Total Balance at December 31, 2019 $ 299 $ 695 $ 369 $ 129 $ 1,492 Provision related to current period sales 652 951 66 64 1,733 Adjustment related to prior period sales (18 ) 59 — — 41 Credit or payments made during the period (498 ) (521 ) — (59 ) (1,078 ) Balance at March 31, 2020 $ 435 $ 1,184 $ 435 $ 134 $ 2,188

Description of the Business - A

Description of the Business - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Accumulated deficit	$ (738,875)	$ (711,258)
Cash, cash equivalents and available for sale marketable securities current	$ 194,800

Summary of Significant Accoun_3

Summary of Significant Accounting Policies and Basis of Presentation - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2020USD ($)Segment	Dec. 31, 2019USD ($)
Accounting Policies [Line Items]
Number of operating segments | Segment	1
Off-balance sheet concentration of credit risk	$ 0
Accounts receivable, net	10,887,000	$ 8,475,000
NUZYRA [Member]
Accounting Policies [Line Items]
Accounts receivable, net	7,200,000
Zai Lab (Shanghai) Co., Ltd. [Member]
Accounting Policies [Line Items]
Accounts receivable, net		$ 3,000,000
BARDA Contract [Member]
Accounting Policies [Line Items]
Accounts receivable, net	300,000
Almirall [Member]
Accounting Policies [Line Items]
Royalty revenue earned but not yet received	$ 400,000

Cash and Cash Equivalents and_3

Cash and Cash Equivalents and Marketable Securities - Summary of Available for Sale Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 69,695	$ 113,003
Unrealized Gains	471	89
Unrealized Losses		(15)
Fair Value	70,166	113,077
U.S. Treasury Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	69,695	113,003
Unrealized Gains	471	89
Unrealized Losses		(15)
Fair Value	$ 70,166	$ 113,077

Cash and Cash Equivalents and_4

Cash and Cash Equivalents and Marketable Securities - Additional Information (Detail) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Cash And Cash Equivalents [Abstract]
Available for sale securities have remaining maturities greater than twelve months	$ 0	$ 0

Restricted Cash - Summary of Re

Restricted Cash - Summary of Reconciliation of Cash, Cash Equivalents, and Restricted Cash Reported Within Condensed Consolidated Statement of Cash Flows (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Restricted Cash And Investments [Abstract]
Cash and cash equivalents	$ 124,624	$ 102,302	$ 81,219
Short-term restricted cash	630	324	266
Long-term restricted cash	2,261	3,007	250
Total cash, cash equivalents and restricted cash shown on the condensed consolidated statement of cash flows	$ 127,515	$ 105,633	$ 81,735	$ 47,502

Restricted Cash - Additional In

Restricted Cash - Additional Information (Detail) - USD ($) $ in Millions	May 01, 2019	Mar. 31, 2020	Dec. 31, 2019
Healthcare Royalty Partners III, L.P [Member]
Restricted Cash And Cash Equivalents Items [Line Items]
Remaining balance in interest reserve account expected to be paid held as long term restricted cash		$ 2	$ 2.7
Royalty Backed Loan Agreement [Member] | Healthcare Royalty Partners III, L.P [Member]
Restricted Cash And Cash Equivalents Items [Line Items]
Line of credit deposits into interest reserve account	$ 4
Estimated interest amount expected to be paid out of interest reserve account held as restricted cash		0.6	0.3
Letters of Credit [Member]
Restricted Cash And Cash Equivalents Items [Line Items]
Letters of credit amount collateralized		$ 0.3	$ 0.3

Inventories, Net - Schedule of

Inventories, Net - Schedule of Inventories (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Work in process	$ 9,598	$ 9,330
Finished goods	3,874	2,249
Total inventories, net	$ 13,472	$ 11,579

Fixed Assets, Net - Schedule of

Fixed Assets, Net - Schedule of Fixed Assets, Net (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Gross fixed assets	$ 3,563	$ 3,563
Less: Accumulated depreciation and amortization	(2,469)	(2,336)
Total fixed assets, net	1,094	1,227
Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Gross fixed assets	866	866
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Gross fixed assets	567	567
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Gross fixed assets	412	412
Computer Software [Member]
Property, Plant and Equipment [Line Items]
Gross fixed assets	798	798
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Gross fixed assets	$ 920	$ 920

Net Loss Per Share - Antidiluti

Net Loss Per Share - Antidilutive Shares Excluded from Computation of Diluted Net Income (Loss) Per Share (Detail) - shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Excluded potentially dilutive securities	19,034,357	18,115,188
Outstanding Convertible Notes [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Excluded potentially dilutive securities	10,377,361	10,377,361
Stock Option [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Excluded potentially dilutive securities	3,309,900	3,815,951
Unvested Restricted Stock Units [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Excluded potentially dilutive securities	4,444,454	2,837,588
Warrants [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Excluded potentially dilutive securities	104,455	104,455
Employee Stock Purchase Plan [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Excluded potentially dilutive securities	798,187	979,833

Government, License and Colla_2

Government, License and Collaboration Agreements - Additional Information (Detail)

Oct. 02, 2018USD ($)

Oct. 31, 2018USD ($)

Dec. 31, 2017USD ($)

Apr. 30, 2017USD ($)

Dec. 31, 2014USD ($)

Jun. 30, 2014

Feb. 28, 1997shares

Mar. 31, 2020USD ($)TreatmentCourseObligation

Dec. 31, 2019USD ($)

Mar. 31, 2019USD ($)

Dec. 31, 2018USD ($)

Dec. 31, 2019USD ($)

Dec. 31, 2017USD ($)

Jan. 31, 2012USD ($)

Jan. 31, 2010USD ($)

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Milestone payment recognized as revenue

$ 7,920,000

$ 1,598,000

Almirall [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Milestone payment recognized as revenue

$ 200,000

Upfront license fee payment received and recognized as revenue

$ 5,000,000

$ 12,000,000

Milestone payments on acceptance of an NDA submission

$ 12,000,000

Number of performance obligations | Obligation

2

Tufts [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Shares issued | shares

1,024

Milestone payments, maximum

$ 300,000

Milestone payments, paid

50,000

Second milestone payment

100,000

Third and final milestone payment due on acceptance of an NDA submission

$ 150,000

Royalty, payable

25,000

Royalty expense

$ 100,000

100,000

Maximum [Member] | Tufts [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

License agreement, sublicensing Fees percent

14.00%

Minimum [Member] | Tufts [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

License agreement, sublicensing Fees percent

10.00%

Collaboration and Royalty Revenue [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Milestone payment recognized as revenue

$ 280,000

$ 251,000

Collaboration and Royalty Revenue [Member] | Almirall [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Adjustment related to decrease estimated revenue to actual revenue from contract with customer

$ 100,000

BARDA Contract [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Contract term

5 years

Option to extend term

10 years

Maximum payment receivable in contract

$ 284,700,000

Term of base period of performance

5 years

Maximum number of years in contract period of performance

10 years

Maximum number of treatment courses of drug product | TreatmentCourse

2,500

Potential additional staged funding for existing FDA PMR commitments

$ 76,800,000

Potential additional staged funding for manufacturing-related requirements

20,400,000

Milestone payment recognized as revenue

$ 300,000

BARDA Contract [Member] | NUZYRA [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Maximum number of treatment courses procured | TreatmentCourse

10,000

Initial funding for development of NUZYRA

$ 59,400,000

Funding to support drug development.

12,700,000

Funding for three additional purchases

$ 115,400,000

Tetraphase License Agreement [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

License agreement expiration date

2023-10

Zai Lab (Shanghai) Co., Ltd. [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Milestone payment recognized as revenue

$ 0

$ 3,000,000

$ 5,000,000

$ 0

Upfront license fee payment received and recognized as revenue

$ 7,500,000

Period of anniversary for first commercial sale of licensed product

11 years

Number of performance obligations | Obligation

2

Zai Lab (Shanghai) Co., Ltd. [Member] | Paratek Bermuda Ltd [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Upfront license fee payment received and recognized as revenue

$ 7,500,000

Milestone payments upon submission of the first regulatory approval application for a licensed product

3,000,000

3,000,000

Milestone payments on acceptance of an NDA submission

$ 5,000,000

Milestone payments upon regulatory approval for a licensed product

$ 6,000,000

Zai Lab (Shanghai) Co., Ltd. [Member] | Paratek Bermuda Ltd [Member] | Maximum [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Eligible to receive potential regulatory milestone payments

6,000,000

Eligible to receive potential commercial milestone payments

$ 40,500,000

Collaborative Research and License Agreement [Member] | Almirall [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Fees received

$ 4,000,000

New Drug Application [Member] | Almirall [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Fees received

$ 1,000,000

Collaborative Research and License Agreement Phase 2 Trials [Member] | Almirall [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Fees received

$ 2,500,000

Collaborative Research and License Agreement Phase 3 Trials [Member] | Almirall [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Fees received

$ 4,000,000

Novartis International Pharmaceutical Ltd [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Advance notice to terminate collaboration agreement

60 days

Royalty based on annual net sales

0.25%

Period of patent claim

10 years

Novartis International Pharmaceutical Ltd [Member] | Other Liabilities [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Liability under collaboration agreement

$ 3,400,000

$ 3,400,000

$ 3,400,000

Novartis International Pharmaceutical Ltd [Member] | Other Current Liabilities [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Liability under collaboration agreement

$ 100,000

Capital Stock - Additional Info

Capital Stock - Additional Information (Detail) - USD ($)	Aug. 01, 2018	Jun. 27, 2017	Dec. 12, 2016	Sep. 30, 2015	Jul. 31, 2019	Mar. 31, 2020	May 06, 2020
Class Of Stock [Line Items]
Proceeds from issuance of common stock						$ 9,092,000
Beneficial owners minimum required percentage of common stock exchanged for warrant						5.00%
Warrants exercisable description						The Warrants are exercisable for a term beginning on the date of issuance and ending on the earlier to occur of five years (or seven years, in the case of the Fifth Amendment Warrant) from the date of issuance or the consummation of certain acquisitions of the Company as set forth in the various agreements for the Warrants.
Term of warrants						5 years
Fifth Amendment [Member]
Class Of Stock [Line Items]
Term of warrants	7 years
Hercules Term Loan [Member]
Class Of Stock [Line Items]
Exercise price of warrants				$ 24.47
Warrants issued to purchase common stock				32,692
Hercules Term Loan [Member] | Second Amendment [Member]
Class Of Stock [Line Items]
Exercise price of warrants			$ 13.46
Warrants issued to purchase common stock			37,148
Hercules Term Loan [Member] | Fifth Amendment [Member]
Class Of Stock [Line Items]
Exercise price of warrants	$ 10.19
Hercules Term Loan [Member] | Hercules Technology II, L.P. [Member]
Class Of Stock [Line Items]
Warrants issued to purchase common stock				16,346
Expected life of options (in years)				5 years
Hercules Term Loan [Member] | Hercules Technology II, L.P. [Member] | Second Amendment [Member]
Class Of Stock [Line Items]
Warrants issued to purchase common stock			18,574
Hercules Term Loan [Member] | Hercules Technology III, L.P. [Member]
Class Of Stock [Line Items]
Warrants issued to purchase common stock				16,346
Expected life of options (in years)				5 years
Hercules Term Loan [Member] | Hercules Technology III, L.P. [Member] | Second Amendment [Member]
Class Of Stock [Line Items]
Warrants issued to purchase common stock			18,574
Hercules Term Loan [Member] | Hercules Capital Inc [Member]
Class Of Stock [Line Items]
Exercise price of warrants		$ 23.26
Warrants issued to purchase common stock		5,374
Hercules Term Loan [Member] | Hercules Capital Inc [Member] | Fifth Amendment [Member]
Class Of Stock [Line Items]
Warrants issued to purchase common stock	19,627
Warrants Expires in 2021 [Member]
Class Of Stock [Line Items]
Warrants outstanding						9,614
Exercise price of warrants						$ 0.15
Warrants expiration year						2021
Subsequent Event [Member]
Class Of Stock [Line Items]
Common stock value, available for future issuance							$ 9,300,000
2019 Sales Agreement [Member] | Jefferies and BTIG [Member]
Class Of Stock [Line Items]
Percentage of proceeds payable as compensation to underwriter					3.00%
Common stock issued on public offering						2,334,107
Proceeds from issuance of common stock						$ 9,100,000
Proceeds payable as commission to underwriter						$ 300,000
2019 Sales Agreement [Member] | Maximum [Member] | Jefferies and BTIG [Member]
Class Of Stock [Line Items]
Common stock for sale					$ 50,000,000

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Accrued interest	$ 4,221	$ 2,264
Accrued compensation	3,632	7,580
Accrued sales allowances	2,188	1,492
Accrued commercial	1,874	1,445
Accrued inventory	1,756	125
Accrued manufacturing	1,713	1,026
Accrued contract research	1,226	1,612
Accrued professional fees	968	876
Accrued legal costs	394	181
Accrued other	128	95
Total	$ 18,100	$ 16,696

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) $ in Millions	Mar. 31, 2020USD ($)
Fair Value Disclosures [Abstract]
Carrying value of debt	$ 175.7

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets and Liabilities Measured at Fair Value (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Assets
Total Assets	$ 70,166	$ 113,077
Total Assets	70,166	113,077
U.S. Treasury Securities [Member]
Assets
Total Assets	70,166	113,077
Quoted Prices in Active Markets (Level 1) [Member]
Assets
Total Assets	70,166	113,077
Quoted Prices in Active Markets (Level 1) [Member] | U.S. Treasury Securities [Member]
Assets
Total Assets	$ 70,166	$ 113,077

Stock-Based and Incentive Com_3

Stock-Based and Incentive Compensation - Summary of Stock-Based Compensation Expense Included in Company's Condensed Consolidated Statements of Operations and Comprehensive loss (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 2,535	$ 3,863
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	587	1,435
Selling, General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 1,948	$ 2,428

Stock-Based and Incentive Com_4

Stock-Based and Incentive Compensation - Schedule of Share-based Payment Award, Stock Options, Weighted-Average Valuation Assumptions (Detail) - Stock Option [Member]	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility	61.90%	64.80%
Risk-free interest rate	1.30%	2.50%
Expected dividend yield	0.00%	0.00%
Expected life of options (in years)	5 years 7 months 6 days	5 years 7 months 6 days

Stock-Based and Incentive Com_5

Stock-Based and Incentive Compensation - Additional Information (Detail)

Dec. 10, 2020

Jan. 02, 2019shares

Jun. 03, 2009

Apr. 30, 2020shares

Jun. 30, 2018shares

Mar. 31, 2020USD ($)InstallmentTranchedshares

Mar. 31, 2019USD ($)

Dec. 31, 2019USD ($)shares

Dec. 31, 2018

Oct. 31, 2018shares

Oct. 04, 2018USD ($)

Jun. 30, 2017shares

Jun. 09, 2015shares

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Options granted under plan

82,400

Stock-based compensation expense | $

$ 2,535,000

$ 3,863,000

2009 Employee Stock Purchase Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Percent of fair value

85.00%

Number of shares available for grant

36,539

2018 Employee Stock Purchase Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Common stock shares, authorized

943,294

Number of shares available for grant

761,648

Maximum aggregate number of shares of common stock that may be purchased under ESPP

943,294

ESPP, eligible employees to purchase shares, offering periods

6 months

ESPP, eligible employees to purchase shares, offering periods, description

The 2018 ESPP allows eligible employees to purchase shares during certain offering periods, which will be six -month periods commencing June 1 and ending November 30 and commencing December 1 and ending May 31 of each year

First offering under the 2018 ESPP, date

Dec. 1, 2018

RSU [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Unrecognized compensation cost related to unvested share-based arrangements | $

$ 14,000,000

Weighted average compensation cost recognition period

1 year 9 months 10 days

PRSUs [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Time-based vesting period

15 months

2015 Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Description of annual increase in percentage of share reserved for issuance

The Share Reserve automatically increases on January 1 of each year, for the period commencing on (and including) January 1, 2016 and ending on (and including) January 1, 2025, in an amount equal to 5% of the total number of shares of common stock outstanding on December 31 of the preceding calendar year.

Share based compensation, increase in shares issued

1,991,387

Percentage of shares

5.00%

Total shares available for future issuance

82,749

2015 Plan [Member] | Employee Stock Option [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Options granted under plan

61,300

2015 Plan [Member] | RSU [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Options granted under plan

2,495,950

2015 Plan [Member] | RSU [Member] | February 2020 [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Time-based vesting period

1 year

Number of vesting installment period | Installment

3

2015 Plan [Member] | RSU [Member] | Tranche One [Member] | Forecast [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting ratio

0.33

2015 Plan [Member] | RSU [Member] | Tranche Two [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting ratio

0.33

2015 Plan [Member] | RSU [Member] | Tranche Three [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting ratio

0.33

2015 Plan [Member] | PRSUs [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Stock-based compensation expense | $

$ 400,000

$ 500,000

Vested shares

136,000

2015 Plan [Member] | PRSUs [Member] | February 2020 [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Stock-based compensation expense | $

$ 0

2015 Plan [Member] | PRSUs [Member] | Tranche One [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting ratio

0.417

0.182

2015 Plan [Member] | PRSUs [Member] | Tranche One [Member] | February 2020 [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting ratio

0.454

2015 Plan [Member] | PRSUs [Member] | Tranche Two [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting ratio

0.417

0.364

2015 Plan [Member] | PRSUs [Member] | Tranche Two [Member] | February 2020 [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting ratio

0.2727

2015 Plan [Member] | PRSUs [Member] | Tranche Three [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting ratio

0.167

0.454

2015 Plan [Member] | PRSUs [Member] | Tranche Three [Member] | February 2020 [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting ratio

0.2727

2015 Plan [Member] | Minimum [Member] | Employee Stock Option [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Time-based vesting period

1 year

2015 Plan [Member] | Maximum [Member] | Employee Stock Option [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Time-based vesting period

4 years

2015 Plan [Member] | Directors, Officers, Employees and Consultants [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Stock options reserved for future issuance

1,200,000

2014 Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Options granted under plan

0

2006 Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Options granted under plan

0

2015 Inducement Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Options granted under plan

0

Common stock shares, authorized

306,500

Maximum aggregate number of shares of common stock that may be purchased under ESPP

306,500

2015 Inducement Plan [Member] | New Employee [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Stock options reserved for future issuance

360,000

2017 Inducement Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Stock options reserved for future issuance

500,000

Total shares available for future issuance

379,666

2017 Inducement Plan [Member] | Employee Stock Option [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Options granted under plan

21,100

2017 Inducement Plan [Member] | RSU [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Options granted under plan

17,600

Time-based vesting period

3 years

Vesting percentage

100.00%

2017 Inducement Plan [Member] | Minimum [Member] | Employee Stock Option [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Time-based vesting period

1 year

2017 Inducement Plan [Member] | Maximum [Member] | Employee Stock Option [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Time-based vesting period

4 years

2017 Inducement Plan [Member] | Employees Entering into Employment Or Returning to Employment [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Stock options reserved for future issuance

1,050,000

550,000

2014 Equity Incentive Plan, 2015 Equity Incentive Plan, and the 2017 Inducement Plan [Member] | Subsequent Event [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Forfeited, outstanding stock options

1,073,891

Revenue Performance Incentive Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of tranches | Tranche

2

Employment termination description

If a participant’s employment terminates prior to December 31, 2022 due to death or disability, the participant will automatically vest in an additional 25% of each tranche of his or her award.

Percentage of additional performance-based cash incentive awards

25.00%

Revenue incentive plan, vesting percentage

100.00%

Revenue incentive plan upon achievement of milestone description

Upon the achievement of a Tranche 1 or Tranche 2 milestone (but not a deemed achievement in connection with a change of control), each participant’s payout in respect of the applicable tranche of his or her award will equal (a) the participant’s then-vested percentage, multiplied by (b) $25 million, multiplied by (c) the participant’s individual percentage allocation of the incentive pool

Payout of revenues to participants | $

$ 25,000,000

Number of trailing days | d

20

Percentage of cash and registered securities of aggregate payment

50.00%

Accrued compensation cost | $

$ 0

Revenue Performance Incentive Plan [Member] | Tranche 1 Milestone [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of equal installments | Installment

4

Payout of revenues to participants | $

$ 25,000,000

Percentage of milestone deemed to be achieved if milestone not achieved prior to change of control

50.00%

Base amount for dividing cumulative product revenue if milestone not achieved prior to change of control | $

$ 300,000,000

Revenue Performance Incentive Plan [Member] | Tranche 2 Milestone [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of equal installments | Installment

4

Payout of revenues to participants | $

$ 25,000,000

Percentage of milestone deemed to be achieved if milestone not achieved prior to change of control

30.00%

Base amount for dividing cumulative product revenue if milestone not achieved prior to change of control | $

$ 600,000,000

Revenue Performance Incentive Plan [Member] | Minimum [Member] | Tranche 1 Milestone [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Cumulative net product revenues | $

300,000,000

Revenue Performance Incentive Plan [Member] | Minimum [Member] | Tranche 2 Milestone [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Cumulative net product revenues | $

$ 600,000,000

Revenue Performance Incentive Plan [Member] | Maximum [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Incentive pool amount plus accrued interest | $

$ 50,000,000

Stock-Based and Incentive Com_6

Stock-Based and Incentive Compensation - Schedule of Share-based Compensation, Stock Options, Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of Shares Outstanding, Beginning Balances	3,236,073
Number of Shares Outstanding, Granted	82,400
Number of Shares Outstanding, Cancelled or forfeited	(8,573)
Number of Shares Outstanding, Ending Balances	3,309,900	3,236,073
Number of Shares Outstanding, Exercisable	2,877,454
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest [Abstract]
Weighted Average Exercise Price, Beginning Balances	$ 15.54
Weighted Average Exercise Price, Ending Balances	15.25	$ 15.54
Weighted Average Exercise Price, Exercisable	$ 16.05
Share-based Compensation Arrangement by Share-based Payment Award, Options, Weighted-Average Remaining Contractual Term (in Years)
Options Outstanding, Weighted-Average Remaining Contractual Term (in Years)	5 years 10 months 13 days	6 years 3 months 18 days
Options Exercisable, Weighted-Average Remaining Contractual Term (in Years)	5 years 5 months 12 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Aggregate Intrinsic Value
Options Outstanding, Aggregate Intrinsic Value	$ 1	$ 90

Stock-Based and Incentive Com_7

Stock-Based and Incentive Compensation - Schedule of Share-based Compensation, RSU, Activity (Detail) - Restricted Stock Units [Member]	3 Months Ended
	Mar. 31, 2020$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested Number of Shares, Beginning Balance | shares	2,305,408
Number of Shares, Granted | shares	2,513,550
Number of Shares, Released | shares	(252,670)
Number of Shares, Forfeited | shares	(121,834)
Unvested Number of Shares, Ending Balance | shares	4,444,454
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Unvested Weighted Average Grant Date Fair Value, Beginning Balance | $ / shares	$ 7.66
Weighted Average Grant Date Fair Value, Granted | $ / shares	3.52
Weighted Average Grant Date Fair Value, Released | $ / shares	8.42
Weighted Average Grant Date Fair Value, Forfeited | $ / shares	9.50
Unvested Weighted Average Grant Date Fair Value, Ending Balance | $ / shares	$ 5.22

Long-Term Debt - Additional Inf

Long-Term Debt - Additional Information (Detail)	Jun. 27, 2019USD ($)	May 01, 2019USD ($)	Feb. 25, 2019USD ($)	Aug. 01, 2018USD ($)	Apr. 23, 2018USD ($)$ / shares	Apr. 18, 2018USD ($)d$ / shares	Dec. 12, 2016USD ($)	Sep. 30, 2015USD ($)	Apr. 30, 2018USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Royalty Backed Loan Agreement [Member]
Debt Instrument [Line Items]
Costs incurred on issuance of debt										$ 1,853,000	$ 1,880,000
Royalty Backed Loan Agreement [Member] | Healthcare Royalty Partners III, L.P [Member]
Debt Instrument [Line Items]
Interest expense										1,000,000
Line of credit facility, borrowing capacity			$ 32,500,000
Proceeds from lines of credit		$ 27,800,000
Line of credit net of lender discount		500,000
Line of credit lender expenses		200,000
Line of credit deposits into interest reserve account		4,000,000
Repayment of other lender fees		$ 1,200,000
Repayments of loan										$ 1,000,000
Interest rate of annual rate			12.00%
Line of credit facility, fee			1.50%
Line of credit maturity period			May 1, 2029
Maximum [Member] | Royalty Backed Loan Agreement [Member] | Healthcare Royalty Partners III, L.P [Member]
Debt Instrument [Line Items]
Line of credit facility, periodic payment			$ 300,000
4.75% Convertible Senior Subordinated Notes due 2024 [Member]
Debt Instrument [Line Items]
Loan maturity date					May 1, 2024
Loan interest rate										5.47%
Loan agreement payment terms					payable on November 1 and May 1 of each year, beginning on November 1, 2018
Debt instrument interest payable beginning date					Nov. 1, 2018
Debt instrument initial conversion rate					62.8931
Debt instrument conversion, principal amount of each note converted					$ 1,000
Debt instrument conversion, conversion price per share | $ / shares					$ 15.90
Debt instrument conversion premium					20.00%
Closing price of the common stock | $ / shares						$ 13.25
Percentage of common stock price						130.00%
Debt instrument, convertible, threshold trading days | d						20
Debt instrument, convertible, threshold consecutive trading days | d						30
Percentage of debt instrument redemption price						100.00%
Debt instrument, debt default, minimum percentage of aggregate principal amount due					25.00%
Net proceeds from issuance of long-term convertible debt									$ 159,000,000
Costs incurred on issuance of debt									$ 6,000,000	$ 4,298,000	4,531,000
Coupon interest expense										2,000,000
Amortization expense on debt issuance costs										$ 200,000
4.75% Convertible Senior Subordinated Notes due 2024 [Member] | J. Wood Capital Advisors LLC [Member]
Debt Instrument [Line Items]
Principal amount outstanding						$ 5,000,000
4.75% Convertible Senior Subordinated Notes due 2024 [Member] | Purchase Agreement [Member]
Debt Instrument [Line Items]
Principal amount outstanding						$ 135,000,000
Debt instrument, interest rate						4.75%
Additional principal amount outstanding						$ 25,000,000
Hercules Term Loan [Member]
Debt Instrument [Line Items]
Principal amount outstanding	$ 100,000,000
Loan agreement description										On June 27, 2019, the Company entered into an Amended and Restated Loan and Security Agreement, or the Loan Agreement, with Hercules Technology III, L.P., certain other lenders, together, the Lenders, and Hercules Capital, Inc. (as agent), under which the Company may borrow up to $100.0 million in multiple tranches, each, a Term Loan Tranche. The Loan Agreement amends and restates in its entirety the Company’s prior Loan and Security Agreement with the Lenders dated as of September 30, 2015 to, among other things, provide for an extension of the scheduled maturity date of the $60.0 million Term Loan Tranche, or the First Tranche, from September 1, 2021 to September 1, 2023, upon certain events set forth in the Loan Agreement, and an extension of the scheduled maturity date of the $10.0 million Term Loan Tranche, or the Second Tranche, and additional Term Loan Tranches (if any), from August 1, 2022 to August 1, 2024, upon certain events set forth in the Loan Agreement.
Loan interest rate description										The interest rate with respect to the First Tranche is a floating per annum rate equal to the greater of (i) 8.50% plus the prime rate as reported from time to time in The Wall Street Journal minus 5.75%, and (ii) 8.50%. The interest rate with respect to the Second Tranche is, and the interest rate with respect to additional Term Loan Tranches (if any) will be, a floating per annum rate equal to the greater of (i) 7.85% plus the prime rate as reported from time to time in The Wall Street Journal minus 5.75%, and (ii) 7.85%.
Loan agreement payment terms										(which can be extended to May 1, 2021 or September 1, 2021, upon certain events set forth in the Loan Agreement), followed by equal monthly payments of principal and interest through the scheduled maturity date.
Additional interest rate on default	5.00%			5.00%
Minimum subordinated debt for event of default				$ 1,000,000
Interest expense										$ 1,700,000
Costs incurred on issuance of debt										$ 299,000	$ 361,000
Hercules Term Loan [Member] | Minimum [Member] | Between September 1, 2020 and January 1, 2021 [Member]
Debt Instrument [Line Items]
Percentage of prepayment										1.00%
Hercules Term Loan [Member] | Maximum [Member] | Between September 1, 2020 and January 1, 2021 [Member]
Debt Instrument [Line Items]
Percentage of prepayment										2.50%
Hercules Term Loan [Member] | First Tranche [Member]
Debt Instrument [Line Items]
Principal amount outstanding								$ 60,000,000
Loan maturity date	Sep. 1, 2023							Sep. 1, 2021
Basis spread on prime rate								5.75%
Loan interest only maturity date								Jan. 1, 2021
Hercules Term Loan [Member] | First Tranche [Member] | Minimum [Member]
Debt Instrument [Line Items]
Loan interest rate								8.50%
Hercules Term Loan [Member] | Second Tranche [Member]
Debt Instrument [Line Items]
Principal amount outstanding							$ 10,000,000
Loan maturity date	Aug. 1, 2024						Aug. 1, 2022
Basis spread on prime rate							5.75%
Loan interest only maturity date							Jan. 1, 2021
Hercules Term Loan [Member] | Second Tranche [Member] | Minimum [Member]
Debt Instrument [Line Items]
Loan interest rate							7.85%
Hercules Term Loan [Member] | Third Tranche [Member]
Debt Instrument [Line Items]
Additional borrowing capacity subject to sole discretion of Hercules	$ 10,000,000
Hercules Term Loan [Member] | Fourth Tranche [Member]
Debt Instrument [Line Items]
Additional borrowing capacity subject to sole discretion of Hercules	10,000,000
Hercules Term Loan [Member] | Fifth Tranche [Member]
Debt Instrument [Line Items]
Additional borrowing capacity subject to sole discretion of Hercules	$ 10,000,000
Hercules Term Loan [Member] | Equal to 4.5% of First Tranche [Member]
Debt Instrument [Line Items]
Principal amount outstanding								$ 50,000,000
End of term charge								4.50%
Hercules Term Loan [Member] | Equal to 2.25% of First Tranche [Member]
Debt Instrument [Line Items]
Principal amount outstanding								$ 10,000,000
End of term charge								2.25%
Hercules Term Loan [Member] | Equal to 6.95% of Second Tranche [Member]
Debt Instrument [Line Items]
End of term charge							6.95%

Long-Term Debt - Summary of Deb

Long-Term Debt - Summary of Debt (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Apr. 30, 2018
Royalty Backed Loan Agreement [Member]
Debt Instrument [Line Items]
Gross proceeds	$ 32,500	$ 32,500
Unamortized debt issuance costs	(1,853)	(1,880)
Carrying value	30,647	30,620
4.75% Convertible Senior Subordinated Notes due 2024 [Member]
Debt Instrument [Line Items]
Gross proceeds	165,000	165,000
Unamortized debt issuance costs	(4,298)	(4,531)	$ (6,000)
Carrying value	160,702	160,469
Hercules Term Loan [Member]
Debt Instrument [Line Items]
Gross proceeds	70,000	70,000
Unamortized debt issuance costs	(299)	(361)
Carrying value	$ 69,701	$ 69,639

Long-Term Debt - Schedule of Fu

Long-Term Debt - Schedule of Future Principal Payments (Detail) - Hercules Term Loan [Member] - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
2021	$ 65,835
2022	4,165
Total	$ 70,000	$ 70,000

Leases - Additional Information

Leases - Additional Information (Detail)	1 Months Ended		3 Months Ended
	Apr. 30, 2015	Jan. 31, 2015	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Oct. 30, 2016ft²	Jul. 31, 2016USD ($)ft²
Leases [Line Items]
Operating lease, liability, current			$ 1,000,000
Operating lease liability, noncurrent			$ 1,838,000	$ 2,095,000
Boston [Member]
Leases [Line Items]
Lease expiration period			2021
Lease terms	4 years
Operating leases beginning date	2015-07		2016-07
Lease agreement rentable of office space | ft²						4,153
Option to extend, operating lease, term						2 years
Lessee operating lease agreement security deposit paid						$ 100,000
Lease expense			$ 49,000
King of Prussia [Member]
Leases [Line Items]
Lease expiration period			2024
Lease terms		6 years
Operating leases beginning date		2015-06	2016-10
Lease agreement rentable of office space | ft²					19,708

Leases - Summary of Lease Costs

Leases - Summary of Lease Costs Recognized Under Topic 842 and Other Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)
Leases [Abstract]
Operating lease cost	$ 255
Variable lease cost	36
Total lease cost	291
Cash paid for amounts included in the measurement of lease liabilities:	$ 292
Weighted average remaining lease term (in years)	3 years 4 months 24 days
Weighted average discount rate	8.75%

Leases - Summary of Future Mini

Leases - Summary of Future Minimum Operating Lease Obligations under Non-cancelable Operating Leases (Detail) $ in Thousands	Mar. 31, 2020USD ($)
Leases [Abstract]
2020	$ 885
2021	964
2022	508
2023	518
2024	396
Total lease payments	3,271
Less: imputed interest	(449)
Total operating lease liabilities	$ 2,822

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 0	$ 0

Product Revenue - Summary of Pr

Product Revenue - Summary of Product Revenue Allowance and Reserve Categories (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)
Disaggregation Of Revenue [Line Items]
Balance at December 31, 2019	$ 1,492
Provision related to current period sales	1,733
Adjustment related to prior period sales	41
Credit or payments made during the period	(1,078)
Balance at March 31, 2020	2,188
Chargebacks, Discounts and Fees [Member]
Disaggregation Of Revenue [Line Items]
Balance at December 31, 2019	299
Provision related to current period sales	652
Adjustment related to prior period sales	(18)
Credit or payments made during the period	(498)
Balance at March 31, 2020	435
Government and Other Rebates [Member]
Disaggregation Of Revenue [Line Items]
Balance at December 31, 2019	695
Provision related to current period sales	951
Adjustment related to prior period sales	59
Credit or payments made during the period	(521)
Balance at March 31, 2020	1,184
Returns [Member]
Disaggregation Of Revenue [Line Items]
Balance at December 31, 2019	369
Provision related to current period sales	66
Balance at March 31, 2020	435
Patient Assistance [Member]
Disaggregation Of Revenue [Line Items]
Balance at December 31, 2019	129
Provision related to current period sales	64
Credit or payments made during the period	(59)
Balance at March 31, 2020	$ 134