Paratek Pharmaceuticals (PRTK) 10-Q 4 May 17 2017 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2017	Apr. 28, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q1
Trading Symbol	PRTK
Entity Registrant Name	PARATEK PHARMACEUTICALS, INC.
Entity Central Index Key	1,178,711
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		27,485,522

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 62,044	$ 52,962
Available-for-sale securities	77,543	75,076
Restricted cash	127	817
Other receivable	35	323
Prepaid and other current assets	3,050	2,922
Total current assets	142,799	132,100
Restricted cash	250	250
Fixed assets, net	2,178	1,188
Intangible assets, net	976	1,015
Goodwill	829	829
Other long-term assets	333	350
Total assets	147,365	135,732
Current liabilities
Accounts payable and other accrued expenses	7,305	10,790
Accrued contract research	11,274	9,566
Current portion of Intermezzo reserve	56	56
Total current liabilities	18,635	20,412
Long-term debt	39,060	38,974
Contingent obligations	424	655
Other liabilities	4,437	4,099
Total liabilities	62,556	64,140
Commitments and contingencies (Note 15)
Stockholders’ equity
Undesignated preferred stock: $0.001 par value; 5,000,000 shares authorized; no shares issued and outstanding
Common stock, $0.001 par value, 100,000,000 shares authorized, 25,742,253 and 23,358,637 shares issued and outstanding at March 31, 2017 and December 31, 2016, respectively	26	23
Additional paid-in capital	493,550	451,947
Accumulated other comprehensive loss	(54)	(16)
Accumulated deficit	(408,713)	(380,362)
Total stockholders’ equity	84,809	71,592
Total liabilities and stockholders’ equity	$ 147,365	$ 135,732

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) (unaudited) - $ / shares	Mar. 31, 2017	Dec. 31, 2016
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	25,742,253	23,358,637
Common stock, shares outstanding	25,742,253	23,358,637

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Revenue:
Royalty Revenue	$ 18
Total Revenue	18
Operating expenses:
Research and development	18,657	$ 24,288
General and administrative	8,363	6,339
Changes in fair value of contingent consideration	(231)	105
Total operating expenses	26,789	30,732
Loss from operations	(26,771)	(30,732)
Other income and expenses:
Interest expense	(1,132)	(730)
Interest income	240	191
Other loss, net	(7)
Net loss	(27,670)	(31,271)
Other comprehensive income:
Unrealized (loss) gain on available-for-sale securities, net of tax	(38)	1
Comprehensive loss	$ (27,708)	$ (31,270)
Net loss per share - basic and diluted	$ (1.14)	$ (1.78)
Weighted average common shares outstanding Basic and diluted	24,196,158	17,615,754

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement Of Cash Flows [Abstract]
Net loss	$ (27,670)	$ (31,271)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	301	244
Stock-based compensation expense	4,044	2,419
Noncash interest expense	293	357
Noncash interest income		(191)
Changes in fair value of contingent consideration	(231)	105
Changes in operating assets and liabilities
Accounts receivable and other current assets	420	4,471
Accounts payable and accrued expenses	(2,439)	5,430
Other liabilities and other assets	355	(74)
Net cash used in operating activities	(24,927)	(18,510)
Investing activities
Purchase of fixed assets, net	(897)	(99)
Purchase of marketable securities	(27,665)	(68,353)
Proceeds from maturities of marketable securities	25,000
Decrease (increase) in restricted cash	690	(947)
Net cash used in investing activities	(2,872)	(69,399)
Financing activities
Proceeds from exercise of stock options	22	11
Proceeds from sale of common stock	36,859	739
Net cash provided by financing activities	36,881	750
Net increase (decrease) in cash and cash equivalents	9,082	(87,159)
Cash and cash equivalents at beginning of period	52,962	131,302
Cash and cash equivalents at end of period	62,044	44,143
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Cash paid for interest	737	$ 430
Purchases of fixed assets in accrued expenses	$ 198

Description of the Business

Description of the Business	3 Months Ended
	Mar. 31, 2017
Accounting Policies [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 clinical stage biopharmaceutical company focused on the development and commercialization of innovative therapeutics based upon tetracycline chemistry. 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 two lead product candidates are the antibacterials omadacycline and sarecycline. The Company has generated innovative small molecule therapeutic candidates based upon medicinal chemistry-based modifications, according to structure-based activity, of all positions of the core tetracycline molecule. These efforts have yielded molecules with broad-spectrum antibiotic properties and narrow-spectrum antibiotic properties, and molecules with potent anti-inflammatory properties to fit specific therapeutic applications. This proprietary chemistry platform has produced many compounds that have shown interesting characteristics in various in vitro in vivo If approved, omadacycline will be the first in a new class of aminomethylcycline antibiotics. Omadacycline is a broad-spectrum, well-tolerated once-daily oral and intravenous, or IV, antibiotic. The Company believes that omadacycline has the potential to become the primary antibiotic choice of physicians for use as a broad-spectrum monotherapy antibiotic for acute bacterial skin and skin structure infections, or ABSSSI, community-acquired bacterial pneumonia, or CABP, urinary tract infection, or UTI, and other serious community-acquired bacterial infections, where resistance is of concern. The Company believes omadacycline, if approved, will be used in the emergency room, hospital and community care settings. The Company has designed omadacycline to provide potential advantages over existing antibiotics, including activity against resistant bacteria, broad spectrum antibacterial activity, oral and IV formulations with once-daily dosing, no known drug interactions, and a favorable safety and tolerability profile. The Company’s second Phase 3 antibacterial product candidate, sarecycline, also known as WC3035, is a new, once-daily, tetracycline-derived compound designed for use in the treatment of acne and rosacea. The Company believes that, based upon the data generated to-date, sarecycline possesses favorable anti-inflammatory activity, plus narrow-spectrum antibacterial activity relative to other tetracycline-derived molecules, oral bioavailability, does not cross the blood-brain barrier, and favorable pharmacokinetic, or PK, properties that the Company believes make it particularly well-suited for the treatment of inflammatory acne in the community setting. The Company has exclusively licensed U.S. development and commercialization rights to sarecycline for the treatment of acne to Allergan plc, or Allergan, while retaining development and commercialization rights in the rest of the world. Prior to October 30, 2014, the name of the Company was Transcept Pharmaceuticals, Inc., or Transcept. On October 30, 2014, Transcept completed a business combination, or the Merger, with privately held Paratek Pharmaceuticals, Inc., or Old Paratek, in accordance with the terms of the Agreement and Plan of Merger and Reorganization, dated as of June 30, 2014, by and among Transcept, Tigris Merger Sub, Inc., Tigris Acquisition Sub, LLC and Old Paratek, or the Merger Agreement. The Company has incurred significant losses since its inception in 1996. The Company has generated an accumulated deficit of $408.7 million through March 31, 2017 and will require substantial additional funding in connection with the Company’s continuing operations to support commercial activities associated with its lead product candidate, omadacycline. B ased upon the Company’s current operating plan, the Company anticipates that its existing cash, cash equivalents and marketable securities will enable the Company to fund its operating expenses and capital expenditure requirements through at least the next twelve months from the filing date of this Quarterly Report on Form 10-Q. Risk Factors

Summary of Significant Accounti

Summary of Significant Accounting Policies and Basis of Presentation	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies and Basis of Presentation	2. Summary of Significant Accounting Policies and Basis of Presentation Summary of Significant Accounting Policies The significant accounting policies and estimates used in preparation of the condensed consolidated financial statements are described in the Company’s audited consolidated financial statements as of and for the year ended December 31, 2016, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016, as filed with the Securities and Exchange Commission, or the SEC, on March 2, 2017. As of January 1, 2017, the Company adopted ASU No. 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting . Balance sheet reclassification Amount ($) Increase to additional paid-in capital resulting from the Company's election to recognize forfeitures as they occur rather than applying an estimated forfeiture rate Additional paid-in-capital 681 Charge to accumulated deficit for cumulative-effect adjustment from adoption of ASU 2016-09 Accumulated deficit 681 There have been no other material changes in the Company’s significant accounting policies during the three months ended March 31, 2017. Basis of Presentation The accompanying condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles of the United States of America, or U.S. GAAP, as found in the Accounting Standards Codification, or ASC, and Accounting Standards Update, 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, 2016, and, in the opinion of management, reflect all normal recurring adjustments necessary for the fair presentation of the Company’s financial position, results of operations and cash flows for the interim periods ended March 31, 2017 and 2016. 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, 2017. 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, 2016, and notes thereto, which are included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016, as filed with the SEC on March 2, 2017. 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., Paratek UK, Ltd and Paratek Bermuda Ltd. All significant intercompany accounts and transactions have been eliminated in consolidation. 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 assets and liabilities in the Company’s financial statements. On an ongoing basis, the Company evaluates its estimates and judgments, including those related to, 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.

Cash and Cash Equivalents and M

Cash and Cash Equivalents and Marketable Securities	3 Months Ended
	Mar. 31, 2017
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, 2017 and December 31, 2016 (in thousands): Amortized Cost Unrealized Gains Unrealized Losses Fair Value March 31, 2017 U.S. treasury securities $ 77,597 $ — $ (54 ) $ 77,543 Total $ 77,597 $ $ (54 ) $ 77,543 December 31, 2016 U.S. treasury securities $ 62,574 $ — $ (18 ) $ 62,556 Government agencies 12,518 2 — 12,520 Total $ 75,092 $ 2 $ (18 ) $ 75,076 No available-for-sale securities held as of March 31, 2017 and December 31, 2016 had remaining maturities greater than one year.

Restricted Cash

Restricted Cash	3 Months Ended
	Mar. 31, 2017
Restricted Cash And Investments [Abstract]
Restricted Cash	4. Restricted Cash Short-term restricted cash Intermezzo Reserve On October 28, 2016, the Company executed a royalty sharing agreement, or the Royalty Sharing Agreement, with the Special Committee of the Company’s Board of Directors, or the Special Committee, a committee established in connection with the Merger. Under the Royalty Sharing Agreement, the Company agreed to pay to the former Transcept stockholders fifty percent of all royalty income received by the Company pursuant to the Purdue Collaboration Agreement (as defined in Note 8, License and Collaboration Agreements) Letter of Credit During the year ended December 31, 2016, the Company obtained a letter of credit in the amount of $0.8 million, which was collateralized with a bank account at a financial institution, to secure value-added tax registration in certain foreign countries. The letter of credit was cancelled by the Company during the quarter ended March 31, 2017. Long-term restricted cash The Company leases its Boston, Massachusetts office space under a non-cancelable operating lease. Refer to Note 15, Commitments and Contingencies 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 March 31, 2017 and December 31, 2016, naming the landlord as beneficiary.

Fixed Assets

Fixed Assets	3 Months Ended
	Mar. 31, 2017
Property Plant And Equipment [Abstract]
Fixed Assets	5. Fixed Assets Fixed assets, net, consists of the following (in thousands): March 31, 2017 December 31, 2016 Office equipment $ 919 $ 443 Computer equipment 511 251 Computer software 787 787 Leasehold improvements 850 137 Construction-in-progress — 391 Gross fixed assets 3,067 2,009 Less: Accumulated depreciation and amortization (889 ) (821 ) Net fixed assets $ 2,178 $ 1,188 During the quarter ended March 31, 2017, the Company purchased $1.2 million and disposed of $0.1 million of fixed assets for its expanded lease space in both its King of Prussia and Boston office facilities.

Intangible Assets, Net

Intangible Assets, Net	3 Months Ended
	Mar. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Intangible Assets, Net	6. Intangible Assets, Net Intangible assets consist of the following (in thousands): March 31, 2017 December 31, 2016 Intermezzo product rights $ 1,410 $ 1,410 TO-2070 asset 170 170 Gross intangible assets 1,580 1,580 Less: Accumulated amortization (604 ) (565 ) Net intangible assets $ 976 $ 1,015 Intermezzo product rights and the TO-2070 license rights were acquired through the Merger. Refer to Note 8, License and Collaboration Agreements, In April 2016, the first generic equivalent of Intermezzo was launched. Although the generic was off the market for a short period, it re-entered in September 2016. Intermezzo product sales have steadily declined since its generic equivalent re-entered the market. As such, the Company performed a recoverability test during the quarter ended March 31, 2017. It was determined that the summation of the undiscounted future cash flow of the Intermezzo product rights exceeded its carrying value. As a result, the Company did not record an impairment charge during the quarter ended March 31, 2017. No impairment was recorded during the year ended December 31, 2016.

Net Loss Per Share Available to

Net Loss Per Share Available to Common Stockholders	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
Net Loss Per Share Available to Common Stockholders	7. Net Loss Per Share Available to Common Stockholders Basic net loss per share available to common stockholders is calculated by dividing the net loss available to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share available to common stockholders is computed by dividing the net loss available to common stockholders 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, stock options, restricted stock units, and warrants to purchase common stock are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share available to common stockholders when their effect is dilutive. The following outstanding shares subject to stock options, restricted stock units, and warrants to purchase common stock 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, 2017 and 2016 as indicated below: March 31, 2017 2016 Excluded potentially dilutive securities (1) Shares subject to outstanding options to purchase common stock 3,452,076 2,827,215 Unvested restricted stock units 955,503 475,500 Shares subject to warrants to purchase common stock 79,454 47,426 Shares issuable under employee stock purchase plan 36,539 36,539 Totals 4,523,572 3,386,680 (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, 2017 and 2016. Such amounts have not been adjusted for the treasury stock method or weighted average outstanding calculations as required if the securities were dilutive.

License and Collaboration Agree

License and Collaboration Agreements	3 Months Ended
	Mar. 31, 2017
Text Block [Abstract]
License and Collaboration Agreements	8. License and Collaboration Agreements Allergan plc In July 2007, the Company and Warner Chilcott Company, Inc. (now part of Allergan plc, or Allergan), entered into a collaborative research and license agreement, or the Allergan Collaboration Agreement, under which the Company granted Allergan an exclusive license to research, develop and commercialize tetracycline products for use in the United States for the treatment of acne and rosacea. 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 converted to a non-exclusive license for the treatment of rosacea as of December 2014. Under the terms of the Allergan Collaboration Agreement, the Company and Allergan are responsible for, and are obligated to use, commercially reasonable efforts to conduct specified development activities for the treatment of acne and, if requested by Allergan, the Company may conduct certain additional development activities to the extent the Company determines in good faith that the Company has the necessary resources available for such activities. Allergan has agreed to reimburse the Company for its costs and expenses, including third-party costs, incurred in conducting any such development activities. Under the terms of the Allergan Collaboration Agreement, Allergan 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 Allergan Collaboration Agreement not to directly or indirectly develop or commercialize any tetracycline compounds in the United States for the treatment of acne and rosacea, and Allergan has agreed during the term of the Allergan 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 agreement. The Company earned an upfront fee in the amount of $4.0 million upon the execution of the Allergan Collaboration Agreement, $1.0 million upon filing of an Investigational New Drug Application in 2010, and $2.5 million upon initiation of Phase 2 trials in 2012. In December 2014, the Company also earned $4.0 million upon initiation of Phase 3 trials associated with the Allergan Collaboration Agreement. In addition, Allergan may be required to pay the Company an aggregate of approximately $17.0 million upon the achievement of specified future regulatory milestones, the next being $5.0 million upon acceptance by the U.S. Food & Drug Administration, or FDA, of a New Drug Application, or NDA, submission. Allergan 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 Allergan Collaboration Agreement, with a standard royalty reduction post patent expiration for such product for the remainder of the royalty term. Allergan’s obligation to pay the Company royalties for each tetracycline compound it commercializes under the Allergan Collaboration Agreement expires on the later of the expiration of the last to expire patent that covers the tetracycline compound in the United States and the date on which generic drugs that compete with the tetracycline compound reach a certain threshold market share in the United States. The Company has not received any amounts or recognized any revenue under this arrangement since 2014. 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 ten 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 may be required to make certain payments of up to $0.3 million to Tufts upon the achievement by products developed under the agreement of specified development and regulatory approval milestones. The Company has already made a payment of $50,000 to Tufts for achieving the first milestone following commencement of the Phase 3 clinical trial for omadacycline. 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 agreed to pay Tufts a percentage, ranging from 10% to 14% (ten percent to fourteen percent), 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 the lesser of 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 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 agreement within a specified time period. Purdue Pharma L.P. In July 2009, the Company and Purdue Pharma L.P., or Purdue Pharma, entered into a license and collaboration agreement, or the Purdue Collaboration Agreement, that grants an exclusive license to Purdue Pharma to commercialize Intermezzo in the United States and pursuant to which: • Purdue Pharma paid the Company a $25.0 million non-refundable license fee in August 2009, and non-refundable intellectual property milestone payments of $10.0 million in each of December 2011 and August 2012; • The Company transferred the Intermezzo NDA to Purdue Pharma, and Purdue Pharma is obligated to assume the expense associated with maintaining the NDA and further development of Intermezzo in the United States, including any expense associated with post-approval studies; • Purdue Pharma is obligated to commercialize Intermezzo in the United States at its expense using commercially reasonable efforts; • Purdue Pharma is obligated to pay the Company tiered base royalties on net sales of Intermezzo in the United States ranging from the mid-teens up to the mid-20% level, with each such royalty tiers subject to an increase by a percentage in the low single digits upon a specified anniversary of regulatory approval of Intermezzo. The base royalty is tiered depending upon the achievement of certain fixed net sales thresholds by Purdue Pharma, which net sales levels reset each year for the purpose of calculating the royalty. The royalty tiers are subject to reductions upon generic entry and patent expiration. Purdue Pharma is obligated to pay royalties until the later of 15 years from the date of first commercial sale in the United States or the expiration of patent claims related to Intermezzo; and • Purdue Pharma is obligated to pay the Company up to an additional $70.0 million upon the achievement of certain net sales targets for Intermezzo in the United States. The Purdue Collaboration Agreement expires on the expiration of Purdue Pharma’s royalty obligations. Purdue Pharma has the right to terminate the Purdue Collaboration Agreement at any time upon advance notice of 180 days. The Purdue Collaboration Agreement is also subject to termination by Purdue Pharma in the event of FDA or governmental action that materially impairs Purdue Pharma’s ability to commercialize Intermezzo or the occurrence of a serious event with respect to the safety of Intermezzo. The Purdue Collaboration Agreement may be terminated by the Company upon Purdue Pharma commencing an action that challenges the validity of Intermezzo related patents or if Purdue Pharma is excluded from participation in federal healthcare programs. The Purdue Collaboration Agreement may be terminated by either party in the event of a material breach by or insolvency of the other party. The Company also granted Purdue Pharma and an associated company the right to negotiate for the commercialization of Intermezzo in Mexico in 2013 but retained the rights to commercialize Intermezzo in the rest of the world. During the first quarter of 2014, Purdue Pharma discontinued use of the Purdue Pharma sales force to actively market Intermezzo to healthcare professionals. In October 2014, the Company announced that its Board of Directors had approved a special dividend of, among other things, the right to receive, on a pro rata basis, 100% of any royalty income received by the Company pursuant to the Purdue Collaboration Agreement and 90% of any cash proceeds from a sale or disposition of Intermezzo, less fees and expenses incurred in connection with such activity, to the extent that either occurred prior to the second anniversary of the closing date of the Merger. On October 28, 2016, in satisfaction of the Company’s payment obligation of the proceeds of sale or disposition of the Intermezzo assets to the former Transcept stockholders under the Merger Agreement, the Company executed the Royalty Sharing Agreement pursuant to which the Company agreed to pay to the former Transcept stockholders fifty percent of all royalty income received by the Company pursuant to the Purdue Collaboration Agreement, net of all costs, fees and expenses incurred by the Company in connection with the Purdue Collaboration Agreement, related agreements, the Intermezzo product and the administration of the royalty income to the former Transcept stockholders. Shin Nippon Biomedical Laboratories Ltd. In September 2013, the Company and Shin Nippon Biomedical Laboratories Ltd., or SNBL, entered into a license agreement, or the SNBL License Agreement, pursuant to which SNBL granted the Company an exclusive worldwide license to commercialize SNBL’s proprietary nasal drug delivery technology to develop TO-2070. The Company was developing TO-2070 as a treatment for acute migraine using SNBL’s proprietary nasal powder drug delivery system. Under the SNBL License Agreement, the Company was required to fund all development and regulatory approval with respect to TO-2070. Pursuant to the SNBL License Agreement, the Company paid an upfront nonrefundable technology license fee of $1.0 million, and the Company was also obligated to pay up to an aggregate of $41.5 million upon the achievement of certain development, regulatory and sales milestones, and tiered, low double-digit royalties on annual net sales of TO-2070. In September 2014, the Company and SNBL entered into a termination agreement and release, or the SNBL Termination Agreement, pursuant to which, among other things, the SNBL License Agreement was terminated and the Company assigned all of its rights, interest and title to the TO-2070 asset to SNBL in exchange for a portion of certain future net revenue received by SNBL as set forth in the SNBL Termination Agreement, up to an aggregate of $2.0 million.

Capital Stock

Capital Stock	3 Months Ended
	Mar. 31, 2017
Equity [Abstract]
Capital Stock	9. Capital Stock In October 2015 and February 2017, Paratek Pharmaceuticals, Inc. entered into Controlled Equity Offering SM 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 Merger. These 9,614 warrants to purchase common stock have an exercise price of $0.15 per share and will, if not exercised, expire in 2021. As described in Note 13, Long-term Debt As described in Note 13, Long-term Debt Long-term Debt Long-term Debt

Accounts Payable and Other Accr

Accounts Payable and Other Accrued Expenses	3 Months Ended
	Mar. 31, 2017
Payables And Accruals [Abstract]
Accounts Payable and Other Accrued Expenses	10. Accounts Payable and Other Accrued Expenses Accounts payable and other accrued expenses consist of the following (in thousands): March 31, 2017 December 31, 2016 Accounts payable $ 2,118 $ 4,418 Accrued legal costs 630 358 Accrued compensation 1,086 2,609 Intermezzo payable 63 49 Accrued professional fees 1,469 1,118 Accrued contract manufacturing 1,649 1,940 Accrued other 290 298 Total $ 7,305 $ 10,790

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2017
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 and government agency securities, accounts receivable, accounts payable, accrued expenses, contingent obligations and the Intermezzo reserve 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 carrying value of the long-term debt approximates its fair value as the interest rate is near current market rates. The fair value of the Company’s long-term debt was determined using Level 3 inputs. Fair values are based on assumptions concerning the amount and timing of estimated future cash flows and assumed discount rates, reflecting varying degrees of perceived risk. The following table presents information about the Company’s financial assets and liabilities that have been measured at fair value as of March 31, 2017 and December 31, 2016, 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, 2017 Assets: U.S. treasury securities $ 77,543 $ — $ — $ 77,543 Total Assets $ 77,543 $ — $ — $ 77,543 Liabilities: Contingent obligations $ — $ — $ 424 $ 424 Total Liabilities $ — $ — $ 424 $ 424 December 31, 2016 Assets: U.S. treasury securities $ 62,556 $ — $ — $ 62,556 Government agencies — 12,520 — 12,520 Total Assets $ 62,556 $ 12,520 $ — $ 75,076 Liabilities: Contingent obligations $ — $ — $ 655 $ 655 Total Liabilities $ — $ — $ 655 $ 655 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. The pricing on government agency securities was primarily sourced from independent third party pricing services, overseen by management, and is based on valuation models that consider standard input factor such as deal quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment spreads, credit information and the bond’s terms and conditions, among other things, and are therefore classified as Level 2. Contingent Consideration On October 28, 2016, in satisfaction of the Company’s payment obligation of the proceeds of sale or disposition of the Intermezzo product rights to the former Transcept stockholders under the Merger Agreement, the Company executed the Royalty Sharing Agreement with the Special Committee. Under the Royalty Sharing Agreement, the Company agreed to pay to the former Transcept stockholders fifty percent of all royalty income received by the Company pursuant to the Purdue Collaboration Agreement, net of all costs, fees and expenses incurred by the Company in connection with the Purdue Collaboration Agreement, related agreements, the Intermezzo product and the administration of the royalty income to the former Transcept stockholders. The Company determined that the Royalty Sharing Agreement represents a modification to the original contingent obligations established under the Merger Agreement in accordance with ASC 805, Business Combinations. The significant unobservable inputs used in the fair value measurement of the contingent obligation to former Transcept stockholders with respect to the Intermezzo product rights as of March 31, 2017 and December 31, 2016 were estimated future Intermezzo product revenues and associated royalties due to the Company as well as the appropriate discount rate given consideration to the market and forecast risk involved. The results of this valuation yielded a decrease in the contingent obligation to former Transcept stockholders of $0.2 million during the three months ended March 31, 2017. Significant increases or decreases in any of those inputs would result in a substantially lower or higher fair value measurement. The following table provides a roll forward of the fair value of contingent obligations categorized as Level 3 instruments, for the three months ended March 31, 2017 (in thousands): Contingent liability— former Transcept stockholders Balances at December 31, 2016 $ 655 Change in fair value (231 ) Balances at March 31, 2017 $ 424

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	12. Stock-Based Compensation As described in Note 2, Summary of Significant Accounting Policies and Basis of Presentation Three months ended March 31, 2017 2016 Research and development expense $ 2,705 $ 697 General and administrative expense 1,339 1,722 Total stock-based compensation expense $ 4,044 $ 2,419 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, 2017 2016 Volatility 76.4 % 73.6 % Weighted average risk-free interest rate 2.0 % 1.4 % Expected dividend yield 0.0 % 0.0 % Expected life of options (in years) 5.8 5.8 Stock Option Plan Activity The number of shares of the Company’s common stock available for issuance under the Paratek Pharmaceuticals, Inc. 2015 Equity Incentive Plan, or the 2015 Plan, was initially 1,200,000 shares. The initial number of shares authorized under the 2015 Plan may be increased by the number of shares that again become available for grant as a result of forfeited or terminated awards or shares withheld in satisfaction of the exercise price or tax withholding obligations associated with awards under the Paratek Pharmaceuticals, Inc. 2006 Incentive Award Plan, as amended, and the Paratek Pharmaceuticals, Inc. 2014 Equity Incentive Plan, with the total amount of the initial shares plus the forfeited or terminated shares not to exceed 2,000,000 shares. During the quarter ended March 31, 2017, the Company’s Board of Directors granted 702,750 stock options and 559,000 restricted stock units 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 restricted stock unit, or RSU, awards made to directors of the Company are subject to time-based vesting, with 100% of the shares of common stock subject to the RSUs vesting one year from the grant date. The grants also included performance-based RSU, or PRSU, awards to certain executives and employees of the Company. The PRSUs will vest as follows: 20% of the PRSUs shall vest upon achievement of data lock for Study 16301 (oral only ABSSSI), or the First Milestone; 30% of the PRSUs shall vest upon achievement of IV and oral NDA acceptances, or the Second Milestone; and 50% of the PRSUs shall vest upon FDA approval of omadacycline, or the Third Milestone, provided, that, each of the First Milestone, the Second Milestone and the Third Milestone must occur no later than the fifth anniversary of the date of grant for the applicable portion of the PRSUs to vest. The Company recognizes compensation cost for awards with performance conditions if and when the Company concludes that it is probable that the performance condition will be achieved over the requisite service period. Since the Company believes it is more likely than not that the First Milestone and Second Milestone will be achieved prior to the fifth anniversary of the date of grant, the Company recognized compensation cost, for a total of $1.0 million, for both performance conditions during the quarter ended March 31, 2017 using the accelerated attribution method. The Company has not made any additional grants under the Paratek Pharmaceuticals, Inc. 2015 Inducement Plan, or the 2015 Inducement Plan, since fiscal year 2015. As of March 31, 2017, no additional shares remained available for issuance under either the Total shares available for future issuance under the 2015 Plan are 271,278 shares as of March 31, 2017. Stock options A summary of stock option activity for the three months ended March 31, 2017 is as follows: Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Outstanding Balances at December 31, 2016 2,780,791 $ 16.63 8.27 $ 8,809 Granted 702,750 15.09 Exercised (1,389 ) 14.05 Expired or Forfeited (30,076 ) 19.30 Balances at March 31, 2017 3,452,076 $ 16.30 8.39 $ 17,235 Exercisable March 31, 2017 1,593,079 $ 15.22 7.73 $ 10,456 Vested and expected to vest March 31, 2017 3,452,076 $ 16.30 8.39 $ 17,235 Restricted Stock Units A summary of restricted stock unit activity for the three months ended March 31, 2017 is as follows: Number of Shares Weighted Average Grant Date Fair Value Unvested balance at December 31, 2016 454,000 $ 19.67 Granted 559,000 15.10 Released (57,497 ) 14.05 Unvested balance at March 31, 2017 955,503 $ 17.33 Total unrecognized compensation expense for all stock-based awards was $26.6 million as of March 31, 2017. This amount will be recognized over a weighted average period of 2.02 years.

Long-Term Debt

Long-Term Debt	3 Months Ended
	Mar. 31, 2017
Debt Disclosure [Abstract]
Long-term Debt	13. Long-term Debt On September 30, 2015, the Company entered into the Loan Agreement with Hercules and certain other lenders, and Hercules Technology Growth Capital, Inc. (as agent). Under the Loan Agreement, Hercules provided the Company with access to term loans with an aggregate principal amount of up to $40.0 million, or collectively, the Term Loan. The Company initially drew a principal amount of $20.0 million, which was funded on September 30, 2015. The remaining $20.0 million under the Loan Agreement was available to be drawn at the Company’s option in minimum increments of $10.0 million through December 31, 2016, or the Draw Period. The Term Loan was repayable in monthly installments commencing on April 1, 2018 through maturity on September 1, 2020. The interest rate was equal to the greater of (i) 8.5%, or (ii) the sum of 8.5%, plus the “prime rate” as reported in The Wall Street Journal minus 5.75% per annum. An end of term charge equal to 4.5% of the issued principal balance of the Term Loan was payable at maturity, including in the event of any prepayment, and was being accrued as interest expense over the term of the loan using the effective interest method. Borrowings under the Loan Agreement were 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 loan together with the prepayment and end of term charges. An Event of Default is defined in the 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 Loan Agreement; (v) insolvency, as described in the 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 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 Loan, which was not due within 12 months of March 31, 2017, has been classified as long-term as the Company determined that a material adverse effect resulting in Hercules exercising its rights under the subjective acceleration clause is remote. Subject to certain terms, pursuant to the Loan Agreement, Hercules was also granted the right to participate in an amount of up to $2.0 million in subsequent sales and issuances of the Company's equity securities to one or more investors for cash for financing purposes in an offering that is broadly marketed to multiple investors and at the same terms as the other investors. On September 30, 2015, Hercules Technology Growth Capital, Inc. entered into a Stock Purchase Agreement with the Company to purchase 44,782 shares of common stock resulting in proceeds to the Company of approximately $1.0 million. The excess of proceeds received by the Company over the fair value of the common stock issued was allocated as a reduction of the fees paid to Hercules in conjunction with obtaining the initial $20.0 million draw of the Term Loan. Debt issuance costs of $511,000 were ratably allocated to the initial $20.0 million draw and the remaining unfunded $20.0 million. Debt issuance costs related to the initial $20.0 million draw were presented on the consolidated balance sheet as a direct deduction from the related debt liability. Issuance costs related to the unfunded amount were capitalized as prepaid asset and were to be amortized ratably through the end of the Draw Period. In connection with the Loan Agreement, 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 the Company’s common stock (32,692 shares of common stock in total) at an exercise price of $24.47 per share. The Hercules Warrants’ total relative fair value of $288,000 at September 30, 2015 was determined using a Black-Scholes option-pricing model. The relative fair value of the Hercules Warrants was included as a discount to the Term Loan and also as a component of additional paid-in capital. See Note 9, Capital Stock In addition to the Hercules Warrants, the Company paid fees to Hercules in conjunction with obtaining the Term Loan. The Hercules Warrants fair value and fees paid to Hercules, an aggregate of $572,000, were ratably allocated to the initial $20.0 million draw and the remaining unfunded $20.0 million. The $208,000 of costs allocated to the initial $20.0 million draw were recorded as a debt discount and are being amortized as additional interest expense over the term of the loan using the effective interest method. The $364,000 of costs allocated to the unfunded $20.0 million was recorded as prepaid expenses and were being amortized ratably through the end of the Draw Period. In the event the Company exercised its option to borrow additional funds, the remaining unamortized prepaid asset balance related would be reclassified and recorded as debt discount based upon a ratable allocation of the amount drawn compared to the remaining unfunded amount available to the Company and would amortize over the remaining life of the term loan using the effective interest method. On December 12, 2016, the Company and Hercules entered into an amendment to the Loan Agreement, or the Loan Agreement Amendment, which extended the date on which the Company must begin making amortization payments under the Loan Agreement from April 1, 2018 to January 1, 2019, or the Amortization Date. Upon commencement of the Amortization Date, the Company will make amortization payments based upon an amortization schedule equal to thirty consecutive months, with the balance of outstanding loans due on the original maturity date of the Loan Agreement. The Loan Agreement Amendment also increased the amount that the Company may borrow by $10.0 million, from up to $40.0 million to up to $50.0 million in multiple tranches. The additional $10.0 million tranche, or the Additional Tranche, is available at the Company’s option through September 15, 2017 conditioned upon the Company completing either a second Phase 3 clinical evaluation of omadacycline in patients with ABSSSI or in patients with CABP supportive of the Company making a NDA filing with the FDA. The Company announced positive top-line efficacy and safety data for the Phase 3 CABP study in April 2017, and as such, the Additional Tranche became available to the Company. If drawn, the Additional Tranche shall bear interest and have the same maturity as all other loans outstanding under the Loan Agreement. The Company borrowed the first tranche of $20.0 million upon the closing of the Loan Agreement on September 30, 2015 and, concurrently with the closing of the Loan Agreement Amendment, the Company borrowed an additional $20.0 million under the Loan Agreement. In connection with the Loan Agreement Amendment, the Company paid Hercules a $0.4 million amendment fee. The end of term charge, discussed above, is equal to 4.5% of the issued principal balance of the Loan Agreement Amendment, and is payable at maturity, including in the event of any prepayment, and is being accrued as interest expense over the term of the loan using the effective interest method. Borrowings under the Loan Agreement Amendment are still collateralized by substantially all of the assets of the Company. If the Company repays all or a portion of the term loans prior to maturity, in addition to the end of term charge, the Company would pay Hercules a prepayment fee as follows: (i) 2.0% of the then outstanding principal amount if the prepayment occurs prior to January 1, 2019 or (ii) no fee if the prepayment occurs on or after January 1, 2019. In connection with the Loan Agreement Amendment, the Company issued the Loan Amendment Warrants to each of Hercules Technology II, L.P. and Hercules Technology III, L.P. which together are exercisable for an aggregate of 37,148 shares of the Company’s common stock at an exercise price of $13.46 per share. Additionally, upon the Additional Tranche funding date, the Company will issue an additional warrant to each of Hercules Technology II, L.P. and Hercules Technology III, L.P. which together will be exercisable for an aggregate number of shares equal to $125,000 divided by the arithmetic mean of the Company’s daily closing price per share for the ten trading days preceding the Additional Tranche funding date and which each carry an exercise price equal to the arithmetic mean of the Company’s daily closing price per share for the ten trading days preceding the Additional Tranche funding date. Each Loan Amendment Warrant may be exercised on a cashless basis. The Loan Amendment Warrants are exercisable for a term beginning on the date of issuance and ending on the earlier to occur of five years from the date of issuance or the consummation of certain acquisitions of the Company as set forth in the Loan Amendment Warrants. The number of shares for which the Loan Amendment Warrants are exercisable and the associated exercise price are subject to certain proportional adjustments as set forth in the Loan Amendment Warrants. As of March 31, 2017, the Company has recorded a long-term debt obligation of $39.1 million, net of debt discount of $0.9 million. Future principal payments, which exclude the 4.5% end of term charge, in connection with the Loan Agreement, as of March 31, 2017 are as follows (in thousands): Fiscal Year 2017 $ — 2018 — 2019 14,952 2020 25,048 2021 and thereafter — Total $ 40,000

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	14 . There is no provision for federal and state income taxes since the Company has historically incurred operating losses. Previously, a component of the Company’s net operating losses related to tax deductions for the stock based compensation in excess of book compensation, or additional paid-in-capital net operating losses, would have been credited to additional paid-in-capital if they became utilizable in future periods. Under ASU 2016-09, any such excess deductions will be added to the existing net operating losses. This is not expected to have a material impact on the Company’s deferred tax assets or related disclosures. 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.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	15. Commitments and Contingencies Leases The Company’s contractual obligations and commitments were reported in its Annual Report on Form 10-K for the year ended December 31, 2016, as filed with the SEC on March 2, 2017. 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 executed the third amendment to the lease agreement on its King of Prussia office space in October 2016. The lease agreement, as amended, is for 19,708 rentable square feet of office space, for a total commitment of $3.3 million with respect to which lease payments became due beginning once Paratek took control of such office space during the first quarter of 2017. The total lease commitment is over a seven-year and seven-month lease term. The lease contains rent escalation and a partial rent abatement period, which is being accounted for as rent expense under the straight-line method. The Company is required to make additional payments under the operating leases for taxes, insurance, and other operating expenses incurred during the operating lease periods. As of March 31, 2017, future minimum lease payments under operating leases are as follows: Fiscal Year Remainder of 2017 $ 528 2018 1,084 2019 1,156 2020 1,178 2021 964 2022 and thereafter 1,422 Total $ 6,332 Intermezzo Patent Litigation In July 2012, the Company received notifications from three companies, Actavis Elizabeth LLC, or Actavis Elizabeth, Watson Laboratories, Inc.—Florida, or Watson, and Novel Laboratories, Inc., or Novel, in September 2012, from each of Par Pharmaceutical, Inc. and Par Formulations Private Ltd., together, the Par Entities, in February 2013 from Dr. Reddy’s Laboratories, Inc. and Dr. Reddy’s Laboratories, Ltd., together, Dr. Reddy’s, and in July 2013 from TWi Pharmaceuticals, Inc., or Twi, stating that each has filed with the FDA an ANDA, that references Intermezzo. Refer to Item 3, Legal Proceedings The United States District Court for the District of New Jersey, or the New Jersey District Court, held a consolidated trial between December 1, 2014 and December 15, 2014 involving Paratek, Purdue Pharma, and their patent infringement claims against Actavis Elizabeth, Novel, and Dr. Reddy’s. The New Jersey District Court then received post-trial briefing and held a February 13, 2015 post-trial hearing. On March 27, 2015, the New Jersey District Court issued an order and accompanying opinion finding that: (a) the asserted claims of U.S. Patent Nos. 7,682,628, 8,242,131, and 8,252,809, are invalid as obvious; (b) Actavis Elizabeth, Novel, and Dr. Reddy’s infringe the ‘131 patent; (c) Novel infringes the ‘628 patent; and (d) Novel and Dr. Reddy’s infringe the ‘809 patent. On April 9, 2015, the New Jersey District Court entered final judgment consistent with the March 27, 2015 opinion and order referenced above. As a result of the New Jersey District Court’s findings, the intangible assets representing Intermezzo product rights were impaired and the related contingent obligation was reduced in light of an expected decline in Intermezzo sales for the three months ended March 31, 2015. The Company and Purdue Pharma jointly appealed the New Jersey District Court’s final judgment as to the '131 patent to the United States Court of Appeals for the Federal Circuit on May 6, 2015. On January 8, 2016, the United States Court of Appeals for the Federal Circuit affirmed the decision of the New Jersey District Court, and no opinion accompanied the judgment. On September 14, 2016, the defendants filed a warrant of satisfaction of judgment in the New Jersey District Court for the costs having been fully paid to the defendants. Patent Term Adjustment Suit In January 2013, the Company filed suit in the Eastern District of Virginia against the United States Patent and Trademark Office, or the USPTO, seeking recalculation of the patent term adjustment of the ’131 Patent. Purdue Pharma has agreed to bear the costs and expenses associated with this litigation. In June 2013, the judge granted a joint motion to stay the proceedings pending a remand to the USPTO, in which the USPTO is expected to reconsider its patent term adjustment award in light of decisions in a number of appeals to the Federal Circuit, including Novartis AG v. Lee 740 F.3d 593 (Fed. Cir. 2014), or the Novartis decision. Since having issued final rules implementing the Novartis decision, the USPTO has been working through the civil action cases and issuing remand decisions. The Company’s case was on remand until the USPTO made its decision on the recalculation of the patent term adjustment. On September 28, 2016, the USPTO issued a decision that the patent term adjustment is 1,038 days, from which the ‘131 Patent expiration would be March 26, 2029. Other Legal Proceedings 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, 2017, the Company was not party to any other legal or arbitration proceedings that may have, or have had in the recent past, significant effects on the Company’s financial position. No governmental proceedings are pending or, to the Company’s knowledge, 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.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2017
Subsequent Events [Abstract]
Subsequent Events	16. Subsequent Events Collaboration Agreement with Zai Lab (Shanghai) Co., Ltd. In April 2017, Paratek Bermuda Ltd., a wholly-owned subsidiary of Paratek Pharmaceuticals, Inc., and Zai Lab (Shanghai) Co., Ltd., or Zai, entered into a License and Collaboration Agreement, or the Zai Collaboration Agreement. Under the terms of the Zai Collaboration Agreement, the Company granted Zai an exclusive license to develop, manufacture and commercialize omadacycline in the People’s Republic of China, Hong Kong, Macau and Taiwan, or the 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 Territory, at its sole cost with certain assistance from the Company. Zai will pay the Company an upfront license fee of $7.5 million and potential regulatory and commercial milestone payments. Zai will also pay the Company tiered royalties at a low double digit to mid-teen percent on net sales of the licensed product in the Territory. The Zai Collaboration Agreement will continue on a region-by-region basis until Zai’s payment of all its payment obligations, unless earlier terminated according to the terms of the Zai Collaboration Agreement.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	3 Months Ended
	Mar. 31, 2017
New Accounting Pronouncements And Changes In Accounting Principles [Abstract]
Recent Accounting Pronouncements	17. 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. Between May 2014 and May 2016, the FASB issued three ASUs changing the requirements for recognizing and reporting revenue, or together, herein referred to as the Revenue ASUs: (i) ASU No. 2014-09, Revenue from Contracts with Customers Principal versus Agent Considerations (Reporting Revenue Gross versus Net), Narrow-Scope Improvements and Practical Expedients Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date, In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) The Company is currently evaluating the impact the adoption of ASU 2016-02 will have on its consolidated financial statements. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230), on its consolidated financial statements. In October 2016, the FASB issued ASU No. 2016-16, Intra-Entity Transfers of Assets Other Than Inventory In November 2016, the FASB issued ASU No. 2016-18, Restricted Cash In January 2017, the FASB issued ASU No. 2017-04, Simplifying the Test for Goodwill Impairment

Summary of Significant Accoun23

Summary of Significant Accounting Policies and Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies The significant accounting policies and estimates used in preparation of the condensed consolidated financial statements are described in the Company’s audited consolidated financial statements as of and for the year ended December 31, 2016, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016, as filed with the Securities and Exchange Commission, or the SEC, on March 2, 2017. As of January 1, 2017, the Company adopted ASU No. 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting . Balance sheet reclassification Amount ($) Increase to additional paid-in capital resulting from the Company's election to recognize forfeitures as they occur rather than applying an estimated forfeiture rate Additional paid-in-capital 681 Charge to accumulated deficit for cumulative-effect adjustment from adoption of ASU 2016-09 Accumulated deficit 681 There have been no other material changes in the Company’s significant accounting policies during the three months ended March 31, 2017.
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles of the United States of America, or U.S. GAAP, as found in the Accounting Standards Codification, or ASC, and Accounting Standards Update, 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, 2016, and, in the opinion of management, reflect all normal recurring adjustments necessary for the fair presentation of the Company’s financial position, results of operations and cash flows for the interim periods ended March 31, 2017 and 2016. 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, 2017. 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, 2016, and notes thereto, which are included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016, as filed with the SEC on March 2, 2017.
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., Paratek UK, Ltd and Paratek Bermuda Ltd. All significant intercompany accounts and transactions have been eliminated in consolidation.
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 assets and liabilities in the Company’s financial statements. On an ongoing basis, the Company evaluates its estimates and judgments, including those related to,
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.

Summary of Significant Accoun24

Summary of Significant Accounting Policies and Basis of Presentation (Tables)	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Summary of Impact to Consolidated Balance Sheet Including Amount Charged to Retained Earnings	The following table summarizes the impact to the Company’s consolidated balance sheet, including the amount charged to retained earnings as of January 1, 2017 (in thousands): Balance sheet reclassification Amount ($) Increase to additional paid-in capital resulting from the Company's election to recognize forfeitures as they occur rather than applying an estimated forfeiture rate Additional paid-in-capital 681 Charge to accumulated deficit for cumulative-effect adjustment from adoption of ASU 2016-09 Accumulated deficit 681

Cash and Cash Equivalents and25

Cash and Cash Equivalents and Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2017
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, 2017 and December 31, 2016 (in thousands): Amortized Cost Unrealized Gains Unrealized Losses Fair Value March 31, 2017 U.S. treasury securities $ 77,597 $ — $ (54 ) $ 77,543 Total $ 77,597 $ $ (54 ) $ 77,543 December 31, 2016 U.S. treasury securities $ 62,574 $ — $ (18 ) $ 62,556 Government agencies 12,518 2 — 12,520 Total $ 75,092 $ 2 $ (18 ) $ 75,076

Fixed Assets (Tables)

Fixed Assets (Tables)	3 Months Ended
	Mar. 31, 2017
Property Plant And Equipment [Abstract]
Schedule of Fixed Assets, Net	Fixed assets, net, consists of the following (in thousands): March 31, 2017 December 31, 2016 Office equipment $ 919 $ 443 Computer equipment 511 251 Computer software 787 787 Leasehold improvements 850 137 Construction-in-progress — 391 Gross fixed assets 3,067 2,009 Less: Accumulated depreciation and amortization (889 ) (821 ) Net fixed assets $ 2,178 $ 1,188

Intangible Assets, Net (Tables)

Intangible Assets, Net (Tables)	3 Months Ended
	Mar. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets	Intangible assets consist of the following (in thousands): March 31, 2017 December 31, 2016 Intermezzo product rights $ 1,410 $ 1,410 TO-2070 asset 170 170 Gross intangible assets 1,580 1,580 Less: Accumulated amortization (604 ) (565 ) Net intangible assets $ 976 $ 1,015

Net Loss Per Share Available 28

Net Loss Per Share Available to Common Stockholders (Tables)	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
Antidilutive Shares Excluded from Computation of Diluted Net Income (Loss) Per Share	The following outstanding shares subject to stock options, restricted stock units, and warrants to purchase common stock 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, 2017 and 2016 as indicated below: March 31, 2017 2016 Excluded potentially dilutive securities (1) Shares subject to outstanding options to purchase common stock 3,452,076 2,827,215 Unvested restricted stock units 955,503 475,500 Shares subject to warrants to purchase common stock 79,454 47,426 Shares issuable under employee stock purchase plan 36,539 36,539 Totals 4,523,572 3,386,680 (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, 2017 and 2016. Such amounts have not been adjusted for the treasury stock method or weighted average outstanding calculations as required if the securities were dilutive.

Accounts Payable and Other Ac29

Accounts Payable and Other Accrued Expenses (Tables)	3 Months Ended
	Mar. 31, 2017
Payables And Accruals [Abstract]
Schedule of Accounts Payable and Other Accrued Expenses	Accounts payable and other accrued expenses consist of the following (in thousands): March 31, 2017 December 31, 2016 Accounts payable $ 2,118 $ 4,418 Accrued legal costs 630 358 Accrued compensation 1,086 2,609 Intermezzo payable 63 49 Accrued professional fees 1,469 1,118 Accrued contract manufacturing 1,649 1,940 Accrued other 290 298 Total $ 7,305 $ 10,790

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2017
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, 2017 Assets: U.S. treasury securities $ 77,543 $ — $ — $ 77,543 Total Assets $ 77,543 $ — $ — $ 77,543 Liabilities: Contingent obligations $ — $ — $ 424 $ 424 Total Liabilities $ — $ — $ 424 $ 424 December 31, 2016 Assets: U.S. treasury securities $ 62,556 $ — $ — $ 62,556 Government agencies — 12,520 — 12,520 Total Assets $ 62,556 $ 12,520 $ — $ 75,076 Liabilities: Contingent obligations $ — $ — $ 655 $ 655 Total Liabilities $ — $ — $ 655 $ 655
Rollforward of Fair Value of Contingent Obligations	The following table provides a roll forward of the fair value of contingent obligations categorized as Level 3 instruments, for the three months ended March 31, 2017 (in thousands): Contingent liability— former Transcept stockholders Balances at December 31, 2016 $ 655 Change in fair value (231 ) Balances at March 31, 2017 $ 424

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock-Based Compensation Expense Included in Company's Consolidated Statements of Operations	The following table presents stock-based compensation expense included in the Company’s condensed consolidated statements of operations (in thousands): Three months ended March 31, 2017 2016 Research and development expense $ 2,705 $ 697 General and administrative expense 1,339 1,722 Total stock-based compensation expense $ 4,044 $ 2,419
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, 2017 2016 Volatility 76.4 % 73.6 % Weighted average risk-free interest rate 2.0 % 1.4 % Expected dividend yield 0.0 % 0.0 % Expected life of options (in years) 5.8 5.8
Schedule of Share-based Compensation, Stock Options, Activity	A summary of stock option activity for the three months ended March 31, 2017 is as follows: Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Outstanding Balances at December 31, 2016 2,780,791 $ 16.63 8.27 $ 8,809 Granted 702,750 15.09 Exercised (1,389 ) 14.05 Expired or Forfeited (30,076 ) 19.30 Balances at March 31, 2017 3,452,076 $ 16.30 8.39 $ 17,235 Exercisable March 31, 2017 1,593,079 $ 15.22 7.73 $ 10,456 Vested and expected to vest March 31, 2017 3,452,076 $ 16.30 8.39 $ 17,235
Schedule of Share-based Compensation, Restricted Stock Unit, Activity	A summary of restricted stock unit activity for the three months ended March 31, 2017 is as follows: Number of Shares Weighted Average Grant Date Fair Value Unvested balance at December 31, 2016 454,000 $ 19.67 Granted 559,000 15.10 Released (57,497 ) 14.05 Unvested balance at March 31, 2017 955,503 $ 17.33

Long-Term Debt (Tables)

Long-Term Debt (Tables)	3 Months Ended
	Mar. 31, 2017
Debt Disclosure [Abstract]
Schedule of Future Principal Payments	Future principal payments, which exclude the 4.5% end of term charge, in connection with the Loan Agreement, as of March 31, 2017 are as follows (in thousands): Fiscal Year 2017 $ — 2018 — 2019 14,952 2020 25,048 2021 and thereafter — Total $ 40,000

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Schedule of Future Minimum Lease Payments Under Operating Leases	As of March 31, 2017, future minimum lease payments under operating leases are as follows: Fiscal Year Remainder of 2017 $ 528 2018 1,084 2019 1,156 2020 1,178 2021 964 2022 and thereafter 1,422 Total $ 6,332

Description of the Business - A

Description of the Business - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Accumulated deficit	$ (408,713)	$ (380,362)

Summary of Significant Accoun35

Summary of Significant Accounting Policies and Basis of Presentation - Summary of Impact to Consolidated Balance Sheet Including Amount Charged to Retained Earnings (Detail) - Accounting Standards Update 2016-09 [Member] $ in Thousands	Jan. 01, 2017USD ($)
Additional Paid-in Capital [Member]
Change In Accounting Estimate [Line Items]
Cumulative-effect adjustment to additional paid-in capital and accumulated deficit	$ 681
Accumulated Deficit [Member]
Change In Accounting Estimate [Line Items]
Cumulative-effect adjustment to additional paid-in capital and accumulated deficit	$ 681

Summary of Significant Accoun36

Summary of Significant Accounting Policies and Basis of Presentation - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2017Segment
Accounting Policies [Abstract]
Number of operating segments	1

Cash and Cash Equivalents and37

Cash and Cash Equivalents and Marketable Securities - Summary of Available for Sale Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 77,597	$ 75,092
Unrealized Gains		2
Unrealized Losses	(54)	(18)
Fair Value	77,543	75,076
U.S. Treasury Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	77,597	62,574
Unrealized Losses	(54)	(18)
Fair Value	$ 77,543	62,556
Government Agencies [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		12,518
Unrealized Gains		2
Fair Value		$ 12,520

Cash and Cash Equivalents and38

Cash and Cash Equivalents and Marketable Securities - Additional Information (Detail) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Cash And Cash Equivalents [Abstract]
Available for sale securities had remaining maturities greater than one year	$ 0	$ 0

Restricted Cash - Additional In

Restricted Cash - Additional Information (Detail) - USD ($) $ in Millions	Oct. 28, 2016	Mar. 31, 2017	Dec. 31, 2016
Restricted Cash And Cash Equivalents Items [Line Items]
Royalty income received but not yet paid		$ 0.1
Intermezzo Reserve		0.1	$ 0.1
Letters of credit amount collateralized			0.8
Letters of Credit [Member]
Restricted Cash And Cash Equivalents Items [Line Items]
Letters of credit amount collateralized		$ 0.3	$ 0.3
Royalty Sharing Agreement [Member] | Transcept Pharmaceuticals, Inc. [Member]
Restricted Cash And Cash Equivalents Items [Line Items]
Percentage of royalty income paid for payment obligation	50.00%

Fixed Assets - Schedule of Fixe

Fixed Assets - Schedule of Fixed Assets, Net (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Gross fixed assets	$ 3,067	$ 2,009
Less: Accumulated depreciation and amortization	(889)	(821)
Net fixed assets	2,178	1,188
Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Gross fixed assets	919	443
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Gross fixed assets	511	251
Computer Software [Member]
Property, Plant and Equipment [Line Items]
Gross fixed assets	787	787
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Gross fixed assets	$ 850	137
Construction-in-progress [Member]
Property, Plant and Equipment [Line Items]
Gross fixed assets		$ 391

Fixed Assets - Additional Infor

Fixed Assets - Additional Information (Detail) - King of Prussia and Boston [Member] $ in Millions	3 Months Ended
	Mar. 31, 2017USD ($)
Property, Plant and Equipment [Line Items]
Purchase of fixed assets	$ 1.2
Disposal of fixed assets	$ 0.1

Intangible Assets, Net - Schedu

Intangible Assets, Net - Schedule of Intangible Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Finite Lived Intangible Assets [Line Items]
Gross intangible assets	$ 1,580	$ 1,580
Less: Accumulated amortization	(604)	(565)
Net intangible assets	976	1,015
Intermezzo Product Rights [Member]
Finite Lived Intangible Assets [Line Items]
Gross intangible assets	1,410	1,410
TO-2070 Asset [Member]
Finite Lived Intangible Assets [Line Items]
Gross intangible assets	$ 170	$ 170

Intangible Assets, Net - Additi

Intangible Assets, Net - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Intermezzo Product Rights [Member]
Finite Lived Intangible Assets [Line Items]
Impairment of intangible assets	$ 0	$ 0

Net Loss Per Share Available 44

Net Loss Per Share Available to Common Stockholders - Antidilutive Shares Excluded from Computation of Diluted Net Income (Loss) Per Share (Detail) - shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Excluded potentially dilutive securities	4,523,572	3,386,680
Stock Option [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Excluded potentially dilutive securities	3,452,076	2,827,215
Unvested Restricted Stock Units [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Excluded potentially dilutive securities	955,503	475,500
Warrants [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Excluded potentially dilutive securities	79,454	47,426
Employee Stock Purchase Plan [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Excluded potentially dilutive securities	36,539	36,539

License and Collaboration Agr45

License and Collaboration Agreements - Additional Information (Detail) - USD ($)

Oct. 28, 2016

Dec. 31, 2014

Oct. 31, 2014

Aug. 31, 2012

Dec. 31, 2011

Jul. 31, 2009

Feb. 28, 1997

Mar. 31, 2017

Jan. 31, 2012

Jan. 31, 2010

Sep. 30, 2014

Sep. 30, 2013

Aug. 31, 2009

Transcept Pharmaceuticals, Inc. [Member] | Royalty Sharing Agreement [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Percentage of royalty income paid for payment obligation

50.00%

Allergan [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Aggregated amount payable future regulatory milestones

$ 17,000,000

Milestone payments on acceptance of an NDA submission

5,000,000

Tufts [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Shares issued

1,024

Milestone payments, maximum

300,000

Milestone payments, paid

50,000

Royalty, payable

$ 25,000

Tufts [Member] | Minimum [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

License agreement, sublicensing Fees percent

10.00%

Tufts [Member] | Maximum [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

License agreement, sublicensing Fees percent

14.00%

Purdue Pharma [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Non-refundable license fees

$ 25,000,000

Range of company tier base royalties on net sales of Intermezzo

From the mid-teens up to the mid-20% level

Validity of collaboration agreement

15 years

Advance notice to terminate collaboration agreement

180 days

Rate of royalty receivable

100.00%

Cash proceeds from sale or disposition of intermezzo

90.00%

Purdue Pharma [Member] | Intellectual Property [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Non-refundable milestone payments made

$ 10,000,000

$ 10,000,000

Purdue Pharma [Member] | Maximum [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Amount receivable on achievement of net sales criteria

$ 70,000,000

SNBL [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Non refundable license fee

$ 1,000,000

Aggregate amount obligated for achievement of certain development

$ 41,500,000

SNBL [Member] | Maximum [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Amount receivable on achievement of net sales criteria

$ 2,000,000

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

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Fees earned

$ 4,000,000

New Drug Application [Member] | Allergan [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Fees earned

$ 1,000,000

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

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Fees earned

$ 2,500,000

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

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Fees earned

$ 4,000,000

Capital Stock - Additional Info

Capital Stock - Additional Information (Detail) - USD ($)	May 01, 2017	Dec. 12, 2016	Sep. 30, 2015	Feb. 28, 2017	Oct. 31, 2015	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017
Class Of Stock [Line Items]
Proceeds from issuance of common stock						$ 36,859,000	$ 739,000
Beneficial owners minimum required percentage of common stock exchanged for warrant						5.00%
Term of warrants						5 years
Warrants exercisable description						The Loan Amendment Warrants are exercisable for a term beginning on the date of issuance and ending on the earlier to occur of five years from the date of issuance or the consummation of certain acquisitions of the Company as set forth in the Loan Amendment Warrants.
Hercules Technology II LP and Hercules Technology III LP [Member] | Loan Agreement Amendment [Member]
Class Of Stock [Line Items]
Additional warrants exercisable		125,000				125,000
Hercules Term Loan [Member]
Class Of Stock [Line Items]
Exercise price of warrants			$ 24.47			$ 13.46		$ 13.46
Warrants issued to purchase common stock			32,692			37,148
Hercules Term Loan [Member] | Hercules Technology II, L.P. [Member]
Class Of Stock [Line Items]
Warrants issued to purchase common stock			16,346			18,574
Expected life of options (in years)			5 years
Hercules Term Loan [Member] | Hercules Technology III, L.P. [Member]
Class Of Stock [Line Items]
Warrants issued to purchase common stock			16,346			18,574
Expected life of options (in years)			5 years
Warrants Expires in 2021 [Member]
Class Of Stock [Line Items]
Warrants outstanding						9,614		9,614
Exercise price of warrants						$ 0.15		$ 0.15
Warrants expiration year						2,021
2015 Sales Agreement [Member] | Cantor [Member]
Class Of Stock [Line Items]
Percentage of proceeds payable as compensation to underwriter					3.00%
Common stock sold, value								$ 50,000,000
Common stock issued on public offering						2,326,119
Proceeds from issuance of common stock						$ 36,900,000
Proceeds payable as commission to underwriter						$ 1,100,000
2017 Sales Agreement [Member] | Cantor [Member]
Class Of Stock [Line Items]
Percentage of proceeds payable as compensation to underwriter				3.00%
Subsequent Event [Member] | 2017 Sales Agreement [Member] | Cantor [Member]
Class Of Stock [Line Items]
Common stock for sale	$ 6,900,000
Common stock issued on public offering	1,854,013
Proceeds from issuance of common stock	$ 41,800,000
Proceeds payable as commission to underwriter	$ 1,300,000
Maximum [Member] | 2015 Sales Agreement [Member] | Cantor [Member]
Class Of Stock [Line Items]
Common stock for sale					$ 50,000,000
Maximum [Member] | 2017 Sales Agreement [Member] | Cantor [Member]
Class Of Stock [Line Items]
Common stock for sale				$ 50,000,000

Accounts Payable and Other Ac47

Accounts Payable and Other Accrued Expenses - Schedule of Accounts Payable and Other Accrued Expenses (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Payables And Accruals [Abstract]
Accounts payable	$ 2,118	$ 4,418
Accrued legal costs	630	358
Accrued compensation	1,086	2,609
Intermezzo payable	63	49
Accrued professional fees	1,469	1,118
Accrued contract manufacturing	1,649	1,940
Accrued other	290	298
Total	$ 7,305	$ 10,790

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets and Liabilities Measured at Fair Value (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Assets
Total Assets	$ 77,543	$ 75,076
Liabilities
Total Liabilities	424	655
Contingent Obligations [Member]
Liabilities
Total Liabilities	424	655
Government Agencies [Member]
Assets
Total Assets		12,520
U.S. Treasury Securities [Member]
Assets
Total Assets	77,543	62,556
Quoted Prices in Active Markets (Level 1) [Member]
Assets
Total Assets	77,543	62,556
Quoted Prices in Active Markets (Level 1) [Member] | U.S. Treasury Securities [Member]
Assets
Total Assets	77,543	62,556
Significant Other Observable Inputs (Level 2) [Member]
Assets
Total Assets		12,520
Significant Other Observable Inputs (Level 2) [Member] | Government Agencies [Member]
Assets
Total Assets		12,520
Significant Unobservable Inputs (Level 3) [Member]
Liabilities
Total Liabilities	424	655
Significant Unobservable Inputs (Level 3) [Member] | Contingent Obligations [Member]
Liabilities
Total Liabilities	$ 424	$ 655

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Thousands	Oct. 28, 2016	Mar. 31, 2017	Mar. 31, 2016
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Changes in fair value of contingent consideration		$ (231)	$ 105
Contingent Obligations [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Changes in fair value of contingent consideration		$ (200)
Transcept Pharmaceuticals, Inc. [Member] | Royalty Sharing Agreement [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Percentage of royalty income paid for payment obligation	50.00%

Fair Value Measurements - Roll

Fair Value Measurements - Roll Forward of Fair Value of Contingent Obligations (Detail) - Contingent Obligations [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balances	$ 655
Change in fair value	(231)
Ending balances	$ 424

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock-Based Compensation Expense Included in Company's Condensed Consolidated Statements of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 4,044	$ 2,419
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	2,705	697
General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 1,339	$ 1,722

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Share-based Payment Award, Stock Options, Weighted-Average Valuation Assumptions (Detail) - Employee Stock Option [Member]	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility	76.40%	73.60%
Weighted average risk-free interest rate	2.00%	1.40%
Expected dividend yield	0.00%	0.00%
Expected life of options (in years)	5 years 9 months 18 days	5 years 9 months 18 days

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ in Thousands	Jan. 02, 2017	Jan. 02, 2016	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted under plan			702,750
Compensation cost recognized			$ 4,044	$ 2,419
Unrecognized compensation cost related to unvested share-based arrangements			$ 26,600
Weighted average compensation cost recognition period			2 years 7 days
2015 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options reserved for future issuance			1,200,000
Description of annual increase in percentage of share reserved for issuance			The number of shares available for issuance will automatically increase 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	1,167,931
Percentage of shares		5.00%
Total shares available for future issuance			271,278
2015 Plan [Member] | Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted under plan			702,750
2015 Plan [Member] | Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted under plan			559,000
Time-based vesting period			1 year
Vesting percentage			100.00%
2015 Plan [Member] | PRSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost recognized			$ 1,000
2015 Plan [Member] | PRSUs [Member] | First Milestone [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			20.00%
2015 Plan [Member] | PRSUs [Member] | Second Milestone [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			30.00%
2015 Plan [Member] | PRSUs [Member] | Third Milestone [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			50.00%
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] | Minimum [Member] | Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Time-based vesting period			1 year
2015 Equity Incentive Plan Including Prior Plans [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options reserved for future issuance			2,000,000
2015 Inducement Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options reserved for future issuance			73,167
Options granted under plan			0
2006 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares remained available for issuance			0
2006 Equity Incentive Plan [Member] | Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options cancelled under plan			2,625		40,708
2014 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares remained available for issuance			0

Stock-Based Compensation - Sc54

Stock-Based Compensation - Schedule of Share-based Compensation, Stock Options, Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of Shares Outstanding, Beginning Balances	2,780,791
Number of Shares Outstanding, Granted	702,750
Number of Shares Outstanding, Exercised	(1,389)
Number of Shares Outstanding, Expired or Forfeited	(30,076)
Number of Shares Outstanding, Ending Balances	3,452,076	2,780,791
Number of Shares Outstanding, Exercisable	1,593,079
Number of Shares Outstanding, Vested and expected to vest	3,452,076
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest [Abstract]
Weighted Average Exercise Price, Beginning Balances	$ 16.63
Weighted Average Exercise Price, Granted	15.09
Weighted Average Exercise Price, Exercised	14.05
Weighted Average Exercise Price, Expired or Forfeited	19.30
Weighted Average Exercise Price, Ending Balances	16.30	$ 16.63
Weighted Average Exercise Price, Exercisable	15.22
Weighted Average Exercise Price, Vested and expected to vest	$ 16.30
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)	8 years 4 months 21 days	8 years 3 months 7 days
Options Exercisable, Weighted-Average Remaining Contractual Term (in Years)	7 years 8 months 23 days
Options Exercisable, Vested and expected to vest, Weighted-Average Remaining Contractual Term (in Years)	8 years 4 months 21 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Aggregate Intrinsic Value
Options Outstanding, Aggregate Intrinsic Value	$ 17,235	$ 8,809
Options Exercisable, Aggregate Intrinsic Value	10,456
Vested and expected to vest, Aggregate Intrinsic Value	$ 17,235

Stock-Based Compensation - Sc55

Stock-Based Compensation - Schedule of Share-based Compensation, Restricted Stock Unit, Activity (Detail) - Restricted Stock Units [Member]	3 Months Ended
	Mar. 31, 2017$ / 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	454,000
Number of Shares, Granted | shares	559,000
Number of Shares, Released | shares	(57,497)
Unvested Number of Shares, Ending Balance | shares	955,503
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	$ 19.67
Weighted Average Grant Date Fair Value, Granted | $ / shares	15.10
Weighted Average Grant Date Fair Value, Released | $ / shares	14.05
Unvested Weighted Average Grant Date Fair Value, Ending Balance | $ / shares	$ 17.33

Long-Term Debt - Additional Inf

Long-Term Debt - Additional Information (Detail) - USD ($)	Dec. 12, 2016	Sep. 30, 2015	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Debt Instrument [Line Items]
Proceeds from issuance of common stock			$ 36,859,000	$ 739,000
Long-term debt			$ 39,060,000		$ 38,974,000
Loan Agreement Amendment [Member]
Debt Instrument [Line Items]
Principal amount outstanding	$ 50,000,000	$ 40,000,000
Initial principal amount drawn	$ 20,000,000	20,000,000
End of term charge	4.50%
Amortization payment start date	Apr. 1, 2018
Amortization payment end date	Jan. 1, 2019
Additional principal amount outstanding	$ 10,000,000
Hercules [Member] | Loan Agreement Amendment [Member]
Debt Instrument [Line Items]
Amendment fee paid	$ 400,000
Hercules Technology II LP and Hercules Technology III LP [Member] | Loan Agreement Amendment [Member]
Debt Instrument [Line Items]
Warrants exercise price	$ 13.46
Warrants exercisable	37,148
Additional warrants exercisable	125,000		125,000
warrants exercisable term	5 years
Hercules Term Loan [Member]
Debt Instrument [Line Items]
Principal amount outstanding		40,000,000
Initial principal amount drawn		20,000,000
Remaining available amount under loan agreement		20,000,000
Minimum incremental option to withdraw on loan		$ 10,000,000
Loan agreement description			Under the Loan Agreement, Hercules provided the Company with access to term loans with an aggregate principal amount of up to $40.0 million, or collectively, the Term Loan. The Company initially drew a principal amount of $20.0 million, which was funded on September 30, 2015. The remaining $20.0 million under the Loan Agreement was available to be drawn at the Company’s option in minimum increments of $10.0 million through December 31, 2016, or the Draw Period.
Loan agreement payment terms			The Term Loan was repayable in monthly installments commencing on April 1, 2018 through maturity on September 1, 2020.
Loan repayment commencement date		Apr. 1, 2018
Loan maturity date		Sep. 1, 2020
Loan interest rate description			The interest rate was equal to the greater of (i) 8.5%, or (ii) the sum of 8.5%, plus the “prime rate” as reported in The Wall Street Journal minus 5.75% per annum.
Basis spread on prime rate		5.75%
End of term charge		4.50%
Additional interest rate on default		5.00%
Minimum subordinated debt for event of default		$ 1,000,000
Debt issuance costs		$ 511,000
Warrants issued to purchase common stock		32,692	37,148
Warrants exercise price		$ 24.47
Fair value of warrants		$ 288,000
Aggregate amount of warrant fair and fees paid		572,000
Cost allocated to debt discount amortized as additional interest expense		208,000
Cost allocated to prepaid expenses and are being amortized		$ 364,000
Long-term debt			$ 39,100,000
Debt discount, net			$ 900,000
Hercules Term Loan [Member] | Prior to January 1, 2019 [Member]
Debt Instrument [Line Items]
Percentage of prepayment			2.00%
Hercules Term Loan [Member] | On Or After January 1, 2019 [Member]
Debt Instrument [Line Items]
Prepayment fee			$ 0
Hercules Term Loan [Member] | Hercules [Member]
Debt Instrument [Line Items]
Rights to purchase common stock, exercised		44,782
Proceeds from issuance of common stock		$ 1,000,000
Hercules Term Loan [Member] | Hercules Technology II, L.P. [Member]
Debt Instrument [Line Items]
Warrants issued to purchase common stock		16,346	18,574
Hercules Term Loan [Member] | Hercules Technology III, L.P. [Member]
Debt Instrument [Line Items]
Warrants issued to purchase common stock		16,346	18,574
Hercules Term Loan [Member] | Minimum [Member]
Debt Instrument [Line Items]
Loan interest rate		8.50%
Hercules Term Loan [Member] | Maximum [Member] | Hercules [Member]
Debt Instrument [Line Items]
Rights granted in subsequent sales and issuance of equity securities		$ 2,000,000

Long-Term Debt - Schedule of Fu

Long-Term Debt - Schedule of Future Principal Payments (Detail) - Hercules Term Loan [Member] $ in Thousands	Mar. 31, 2017USD ($)
Debt Instrument [Line Items]
2,019	$ 14,952
2,020	25,048
Total	$ 40,000

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2017USD ($)
Income Tax Disclosure [Abstract]
Provision for federal income taxes	$ 0
Provision for state income taxes	$ 0

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	Sep. 28, 2016	Oct. 31, 2016USD ($)ft²	Mar. 31, 2017
131 Patent [Member]
Operating Leased Assets [Line Items]
Patent term adjustment	1038 days
Patent expiration period	Mar. 26, 2029
Boston [Member]
Operating Leased Assets [Line Items]
Lease expiration period			2,021
King of Prussia [Member]
Operating Leased Assets [Line Items]
Lease expiration period			2,024
Operating leases beginning date		2016-10
Operating lease, additional office space rented | ft²		19,708
Operating lease, total commitment | $		$ 3.3
Lease terms		7 years 7 months

Commitments and Contingencies60

Commitments and Contingencies - Schedule of Future Minimum Lease Payments Under Operating Leases (Detail) $ in Thousands	Mar. 31, 2017USD ($)
Commitments And Contingencies Disclosure [Abstract]
Remainder of 2017	$ 528
2,018	1,084
2,019	1,156
2,020	1,178
2,021	964
2022 and thereafter	1,422
Total	$ 6,332

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) $ in Millions	Apr. 30, 2017USD ($)
Subsequent Event [Member] | Zai Lab (Shanghai) Co., Ltd. [Member]
Subsequent Event [Line Items]
Aggregated amount payable future regulatory milestones	$ 7.5