Gyre Therapeutics (GYRE) 10-Q 2 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	Apr. 30, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Trading Symbol	CBIO
Entity Registrant Name	CATALYST BIOSCIENCES, INC.
Entity Central Index Key	0001124105
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		11,980,103

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 25,024	$ 31,213
Short-term investments	80,253	88,914
Restricted cash	50	50
Prepaid and other current assets	3,675	3,814
Total current assets	109,002	123,991
Other assets, noncurrent	197	543
Right-of-use assets	2,315
Property and equipment, net	356	386
Total assets	111,870	124,920
Current liabilities:
Accounts payable	282	1,248
Accrued compensation	876	1,495
Other accrued liabilities	2,762	2,043
Deferred rent, current portion		15
Operating lease liability	450
Total current liabilities	4,370	4,801
Operating lease liability, noncurrent	1,686
Deferred rent, noncurrent portion		174
Total liabilities	6,056	4,975
Stockholders’ equity:
Preferred stock, $0.001 par value, 5,000,000 shares authorized; zero shares issued and outstanding
Common stock, $0.001 par value, 100,000,000 shares authorized; 11,974,104 and 11,954,528 shares issued and outstanding at March 31, 2019 and December 31, 2018, respectively	12	12
Additional paid-in capital	324,214	323,279
Accumulated other comprehensive income (loss)	13	(4)
Accumulated deficit	(218,425)	(203,342)
Total stockholders’ equity	105,814	119,945
Total liabilities and stockholders’ equity	$ 111,870	$ 124,920

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
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	11,974,104	11,954,528
Common stock, shares outstanding	11,974,104	11,954,528

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Contract revenue		$ 6
Type of Revenue [Extensible List]	cbio:ContractMember	cbio:ContractMember
Operating expenses:
Research and development	$ 12,027	$ 3,771
General and administrative	3,687	2,914
Total operating expenses	15,714	6,685
Loss from operations	(15,714)	(6,679)
Interest and other income, net	631	1,637
Net loss	$ (15,083)	$ (5,042)
Net loss per share attributable to common stockholders, basic and diluted	$ (1.26)	$ (0.56)
Shares used to compute net loss per share attributable to common stockholders, basic and diluted	11,963,586	8,989,669

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (15,083)	$ (5,042)
Other comprehensive income (loss):
Unrealized gain (loss) on available-for-sale securities	17	(4)
Total comprehensive loss	$ (15,066)	$ (5,046)

Condensed Consolidated Statem_3

Condensed Consolidated Statement of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Convertible Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance at Dec. 31, 2017	$ 30,774		$ 6	$ 204,262		$ (173,494)
Balance (in shares) at Dec. 31, 2017		3,680	6,081,230
Opening balance adjustment - adoption of ASC 606 at Dec. 31, 2017	207					207
Balance at Dec. 31, 2017	30,981		$ 6	204,262		(173,287)
Stock-based compensation expense	606			606
Issuance of common stock for secondary public offering, net of issuance costs	106,762		$ 4	106,758
Issuance of common stock for secondary public offering, net of issuance costs, shares			3,382,352
Issuance of common stock upon exercise of warrants	9,545		$ 2	9,543
Issuance of common stock upon exercise of warrants, shares			1,735,419
Conversion of preferred stock to common stock, shares		(3,680)	736,000
Issuance of common stock from stock grants and option exercises, shares			59
Conversion of redeemable convertible notes to common stock, value	3			3
Conversion of redeemable convertible notes to common stock, shares			21
Unrealized gain (loss) on available-for-sale securities	(4)				$ (4)
Net loss	(5,042)					(5,042)
Balance at Mar. 31, 2018	142,851		$ 12	321,172	(4)	(178,329)
Balance (in shares) at Mar. 31, 2018			11,935,081
Balance at Dec. 31, 2018	119,945		$ 12	323,279	(4)	(203,342)
Balance (in shares) at Dec. 31, 2018			11,954,528
Stock-based compensation expense	829			829
Issuance of common stock from stock grants and option exercises	106			106
Issuance of common stock from stock grants and option exercises, shares			19,576
Unrealized gain (loss) on available-for-sale securities	17				17
Net loss	(15,083)					(15,083)
Balance at Mar. 31, 2019	$ 105,814		$ 12	$ 324,214	$ 13	$ (218,425)
Balance (in shares) at Mar. 31, 2019			11,974,104

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Operating Activities
Net loss		$ (15,083)	$ (5,042)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense		829	606
Depreciation and amortization		45	33
Loss on disposal of property and equipment			116
Changes in operating assets and liabilities:
Prepaid and other current assets		96	(407)
Accounts payable		(966)	690
Accrued compensation and other accrued liabilities		100	(1,225)
Change in operating lease liability and right-of-use asset		21
Deferred rent			128
Deferred revenue			(6)
Net cash flows used in operating activities		(14,958)	(5,107)
Investing Activities
Proceeds from maturities of short-term investments		48,274	13,937
Purchase of investments		(39,596)	(12,936)
Purchases of property and equipment		(15)	(198)
Net cash flows provided by investing activities		8,663	803
Financing Activities
Payments for the redemption of redeemable convertible notes			(5,082)
Issuance of common stock for secondary public offering, net of issuance costs			106,761
Issuance of common stock from stock grants and option exercises		106
Proceeds from exercise of warrants			9,545
Net cash flow provided by financing activities		106	111,224
Net increase (decrease) in cash, cash equivalents and restricted cash		(6,189)	106,920
Cash, cash equivalents and restricted cash at beginning of the period		31,263	19,805
Cash, cash equivalents and restricted cash at end of the period	[1]	25,074	126,725
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Adoption of ASC 606			207
Conversion of redeemable convertible notes to common stock			3
Unrealized gain on investments		17	$ 4
Right-of-use asset and operating lease liability recorded upon the adoption of ASC 842, net		$ 2,052
[1]	The following table provides a reconciliation of cash and restricted cash to amounts reported within the condensed consolidated balance sheets:

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019		Dec. 31, 2018	Mar. 31, 2018		Dec. 31, 2017
Statement Of Cash Flows [Abstract]
Cash and cash equivalents	$ 25,024		$ 31,213	$ 126,550
Restricted cash	50		50	175
Total cash and restricted cash	$ 25,074	[1]	$ 31,263	$ 126,725	[1]	$ 19,805
[1]	The following table provides a reconciliation of cash and restricted cash to amounts reported within the condensed consolidated balance sheets:

Nature of Operations and Liquid

Nature of Operations and Liquidity	3 Months Ended
	Mar. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of Operations and Liquidity	1. Catalyst Biosciences, Inc. and its subsidiary (the “Company” or “Catalyst”) is a clinical-stage biopharmaceutical company focused on developing novel treatments for hemophilia and other rare bleeding disorders using our engineered subcutaneous (SQ) coagulation factors that promote blood clotting. Our facilities are located in South San Francisco, California and we operate in one segment. Prior to August 20, 2015, the name of the Company was Targacept, Inc. (“Targacept”). On August 20, 2015, Targacept completed its business combination with Catalyst. The Company had a net loss of $15.1 million for the quarter ended March 31, 2019 and an accumulated deficit of $218.4 million as of March 31, 2019 and expects to continue to incur losses for the next several years. As of March 31, 2019, we had $105.3 million of cash, cash equivalents and short-term investments. Our primary uses of cash are to fund operating expenses, including research and development expenditures and general and administrative expenditures. Based on the current status of its research and development plans, the Company believes that its existing cash, cash equivalents and short-term investments as of March 31, 2019 will be sufficient to fund its cash requirements for at least the next 12 months from the date of the filing of this quarterly report. If, at any time, the Company’s prospects for financing its research and development programs decline, the Company may decide to reduce research and development expenses by delaying, discontinuing or reducing its funding of one or more of its research or development programs. Alternatively, the Company might raise funds through strategic collaborations, public or private financings or other arrangements. Such funding, if needed, may not be available on favorable terms, or at all.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Basis of Presentation The Company’s condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) and following the requirements of the Securities and Exchange Commission (the “SEC”) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. These financial statements have been prepared on the same basis as the Company’s annual financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments, which are necessary for a fair presentation of the Company’s financial information. These interim results and cash flows for any interim period are not necessarily indicative of the results to be expected for the full year. The accompanying condensed consolidated financial statements and related financial information should be read in conjunction with the consolidated financial statements filed with the Company’s Annual Report on Form 10-K for the year ended December 31, 2018 (“Annual Report”). Accounting Pronouncements Recently Adopted The Company’s significant accounting policies are included in “Part II - Item 8 - Financial Statements and Supplementary Data - Note 3 – Summary of Significant Accounting Policies” in the Company’s Annual Report. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), to enhance the transparency and comparability of financial reporting related to leasing arrangements. The Company adopted the standard effective January 1, 2019. As discussed in our Annual Report, the Company adopted the new lease standards in the first quarter of 2019. There have been no other significant changes to these accounting policies during the first three months of 2019. At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present. Operating lease liabilities and their corresponding right-of-use assets are recorded based on the present value of lease payments over the expected lease term. The interest rate implicit in lease contracts is typically not readily determinable. As such, the Company utilizes its incremental borrowing rate, which is the rate incurred to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment. Certain adjustments to the right-of-use asset may be required for items such as initial direct costs paid or incentives received. The Company has elected to combine lease and non-lease components as a single component. The lease expense is recognized over the expected term on a straight-line basis. Operating leases are recognized on the balance sheet as right-of-use assets, operating lease liabilities, current and operating lease liabilities, non-current. As a result, the Company no longer recognizes deferred rent on the balance sheet. On January 1, 2019, the Company adopted the new lease accounting standard using the optional transition method under which comparative financial information is not restated and continues to apply the provisions of the previous lease accounting standard in its financial disclosures for the comparative periods. The Company also elected relevant optional practical expedients including 1) did not reassess whether expired or existing contracts are or contain a lease, 2) did not reassess the lease classifications or reassess the initial direct costs associated with expired or existing leases, and 3) did not separate lease and non-lease components of its operating leases in which it is the lessee. The adoption of the new lease accounting standard had an impact of approximately $2.1 million on the Company's assets and liabilities and had no impact on cash provided by or used in operating, investing or financing activities on the Company's condensed consolidated statements of cash flows. The adoption of the new lease accounting standard did not impact previously reported financial results.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. For a description of the fair value hierarchy and the Company’s fair value methodology, see “ Part II - Item 8 - Financial Statements and Supplementary Data - Note 2 – Summary of Significant Accounting Policies There were no transfers in or out of Level 1 or 2 during the periods presented. The following tables present the fair value hierarchy for assets and liabilities measured at fair value on a recurring basis as of March 31, 2019 and December 31, 2018 ( in thousands March 31, 2019 Level 1 Level 2 Level 3 Total Financial assets: Money market funds ( 1) $ 23,475 $ — $ — $ 23,475 U.S. government agency securities ( 2) 65,653 — 65,653 Federal agency securities ( 2) — 14,600 — 14,600 Restricted cash (money market funds) 50 — — 50 Total financial assets $ 89,178 $ 14,600 $ — $ 103,778 (1) Included in cash and cash equivalents on accompanying condensed consolidated balance sheets. ( 2 ) Included in short-term investments on accompanying condensed consolidated balance sheets and are classified as available-for-sale securities. December 31, 2018 Level 1 Level 2 Level 3 Total Financial assets: Money market funds ( 1) $ 29,090 $ — $ — $ 29,090 Federal agency securities ( 1) — 999 — 999 U.S. Treasury securities ( 2) 74,139 74,139 Federal agency securities ( 2) 14,775 — 14,775 Restricted cash (money market funds) 50 — — 50 Total financial assets $ 103,279 $ 15,774 $ — $ 119,053 (1) Included in cash and cash equivalents on accompanying condensed consolidated balance sheets. ( 2 ) Included in short-term investments on accompanying condensed consolidated balance sheets and are classified as available-for-sale securities.

Financial Instruments

Financial Instruments	3 Months Ended
	Mar. 31, 2019
Investments All Other Investments [Abstract]
Financial Instruments	4. Cash equivalents, restricted cash and short-term investments (debt securities) which are classified as available-for-sale securities, consisted of the following ( in thousands March 31, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Money market funds (cash equivalents) $ 23,475 $ — $ — $ 23,475 U.S. government agency securities 65,645 9 (1 ) 65,653 Federal agency securities 14,595 5 — 14,600 Restricted cash (money market funds) 50 — — 50 Total financial assets $ 103,765 $ 14 $ (1 ) $ 103,778 Classified as: Cash and cash equivalents $ 23,475 Short-term investments 80,253 Restricted cash (money market funds) 50 $ 103,778 December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Money market funds (cash equivalents) $ 29,090 $ — $ — $ 29,090 Federal agency securities (cash equivalents) 999 — — 999 Restricted cash (money market funds) 50 — — 50 U.S. government agency securities 74,144 1 (6 ) 74,139 Agency securities 14,774 1 — 14,775 Total financial assets $ 119,057 $ 2 $ (6 ) $ 119,053 Classified as: Cash and cash equivalents $ 30,089 Short-term investments 88,914 Restricted cash (money market funds) 50 $ 119,053 There have been no material realized gains or losses on available-for-sale securities for the periods presented. The carrying amounts of cash, accounts payable, and other payables approximate their fair values due to the short-term maturity of these instruments. As of March 31, 2019, the remaining contractual maturities of available-for-sale securities was less than one year.

Lease

Lease	3 Months Ended
	Mar. 31, 2019
Lessee Disclosure [Abstract]
Lease	5. The Company leases office space for its corporate headquarters, located in South San Francisco, CA. The lease term is through April 30, 2023 and there are no stated renewal options. Operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term. In calculating the present value of the lease payments, the Company has elected to utilize its incremental borrowing rate based on the original lease term and not the remaining lease term. The lease includes non-lease components ( e.g. For the three months ended March 31, 2019, the Company’s operating lease expense was $0.2 million. The present value assumptions used in calculating the present value of the lease payments were as follows: Weighted-average remaining lease term 4.1 years Weighted-average discount rate 6.0 % Future lease payments under non-cancelable leases as of March 31, 2019 were as follows: Remaining in 2019 $ 423 2020 578 2021 596 2022 613 2023 209 Total future minimum lease payments 2,419 Less imputed interest (283 ) Total lease liability $ 2,136

Stock Based Compensation

Stock Based Compensation	3 Months Ended
	Mar. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Based Compensation	6. The following table summarizes stock option activity under the Company’s equity incentive plans and related information: Number of Shares Underlying Outstanding Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (Years) Outstanding — December 31, 2018 1,361,977 $ 12.04 8.71 Options granted 309,300 $ 8.12 Options exercised (12,794 ) $ 4.60 Options forfeited (39,971 ) $ 7.60 Options Expired (5,641 ) $ 91.79 Outstanding — March 31, 2019 1,612,871 $ 11.17 8.77 Exercisable — March 31, 2019 468,193 $ 16.19 8.03 Vested and expected to vest — March 31, 2019 1,612,871 $ 11.17 8.77 Valuation Assumptions The Company estimated the fair value of stock options granted using the Black-Scholes option-pricing formula and a single option award approach. Due to its limited history as a public company and limited number of sales of its common stock, the Company estimated its volatility considering a number of factors including the use of the volatility of comparable public companies. The expected term of options granted under the Plan, all of which qualify as “plain vanilla” per SEC Staff Accounting Bulletin 107, is determined based on the simplified method due to the Company’s limited operating history and is 6.03 years based on the average between the vesting period and the contractual life of the option. The risk-free rate is based on the yield of a U.S. Treasury security with a term consistent with the option. This fair value is being amortized ratably over the requisite service periods of the awards, which is generally the vesting period. The fair value of employee stock options was estimated using the following weighted-average assumptions for the three months ended March 31, 2019 and 2018: Three Months Ended March 31, 2019 2018 Employee Stock Options: Risk-free interest rate 2.56 % 2.40 % Expected term (in years) 6.03 6.01 Dividend yield — — Volatility 82.91 % 109.32 % Weighted-average fair value of stock options granted $ 5.80 $ 12.34 Total stock-based compensation recognized was as follows ( in thousands Three Months Ended March 31, 2019 2018 Research and development $ 238 $ 115 General and administrative ( 1) 591 491 Total stock-based compensation $ 829 $ 606 (1) 2018 includes $0.1 million in modification stock-based compensation expense related to a Board member’s departure. As of March 31, 2019, 1,031,456 shares of common stock were available for future grant and 1,612,871 options to purchase shares of common stock were outstanding. As of March 31, 2019, the Company had unrecognized employee stock-based compensation expense of $7.4 million, related to unvested stock awards, which is expected to be recognized over an estimated weighted-average period of 2.93 years.

Collaborations

Collaborations	3 Months Ended
	Mar. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaborations	7 . Pfizer Pursuant to the termination agreement entered into on December 8, 2016, in connection with the termination of a prior license and development agreement, Pfizer granted the Company an exclusive license to Pfizer’s proprietary rights for manufacturing materials and processes that apply to Factor VIIa variants, CB 813a and marzeptacog alfa (activated) - MarzAA. Pfizer also transferred to the Company the IND application and documentation related to the development, manufacturing and testing of the Factor VIIa products as well as the orphan drug designation. The Company agreed to make contingent cash payments to Pfizer in an aggregate amount equal to up to $17.5 million, payable upon the achievement of clinical, regulatory and commercial milestones. Following commercialization of any covered product, Pfizer will also receive a single-digit royalty on net product sales on a country-by-country basis for a predefined royalty term. In February 2018, the Company paid Pfizer a $1 million milestone payment based on the dosing of the first patient in its ongoing Phase 2 study; the amount was recorded as a research and development expense. No payments were made to Pfizer in the first quarter of 2019. ISU Abxis In December 2018, the Company entered into an amended and restated license agreement with ISU Abxis (the “A&R ISU Abxis Agreement”), which amended and restated its previous license and collaboration agreement with ISU Abxis previously entered into in September 2013, as subsequently amended in October 2014 and December 2016 (the “Original ISU Abxis Agreement”) ISU Abxis will receive commercialization rights in South Korea to our engineered Factor IX dalcinonacog alfa - DalcA and the Company will receive clinical development and commercialization rights in the rest of world (excluding South Korea) and manufacturing development and manufacturing rights worldwide (including South Korea) The eliminates the profit-sharing arrangement in the Original ISU Abxis Agreement and rovides for a low single-digit royalty payment to ISU Abxis, on a country-by-country basis, for net product sales of DalcA by the Company or its affiliates in each country other than South Korea. Pursuant to the A&R , the Company will also pay up to an aggregate of $19.5 million in milestone payments to ISU Abxis, including $2.5 million in regulatory and development milestone payments and up to $17 million in commercial milestone payments, if the applicable milestones are met.

Net Loss per Share Attributable

Net Loss per Share Attributable to Common Stockholders	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Net Loss per Share Attributable to Common Stockholders	8. The following table sets forth the computation of the basic and diluted net loss per common share during the three months ended March 31, 2019 and 2018 ( in thousands, except share and per share data Three Months Ended March 31, 2019 2018 Net loss attributable to common stockholders $ (15,083 ) $ (5,042 ) Weighted-average number of shares used in computing net loss per share, basic and diluted 11,963,586 8,989,669 Net loss available for common stockholders per share, basic and diluted $ (1.26 ) $ (0.56 ) Since the Company was in a loss position for all periods presented, diluted net loss per share is the same as basic net loss per share for all periods as the inclusion of all potential common shares outstanding would have been anti-dilutive. Potentially dilutive securities on an as-if converted basis that were not included in the diluted per share calculations because they would be anti-dilutive were as follows: Three Months Ended March 31, 2019 2018 Options to purchase common stock 1,612,871 1,026,393 Common stock warrants 10,194 12,039 Redeemable convertible notes — — Total 1,623,065 1,038,432

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Stockholders' Equity	9. Stockholders’ Equity February 2018 Underwritten Public Offering — On February 13, 2018, the Company entered into an underwriting agreement with JonesTrading, in connection with a registered firm commitment underwritten public offering of 2,941,176 shares of common stock, pursuant to a shelf registration statement that was declared effective by the SEC on February 6, 2018. On February 15, 2018, the Company sold 3,382,352 shares of common stock (including 441,176 shares of common stock sold pursuant to the exercise of the underwriters’ overallotment option) at a price to the public of $34.00 per share. The net proceeds to the Company, after deducting the underwriting discounts and commissions and offering expenses payable by the Company were approximately $106.8 million.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. Commitments and Contingencies Manufacturing Agreements On May 20, 2016, the Company signed a development and manufacturing services agreement with AGC Biologics, Inc. (“AGC”), formerly known as CMC ICOS Biologics, Inc., pursuant to which AGC will conduct manufacturing development of agreed upon product candidates. The Company currently has firm work orders with AGC to manufacture MarzAA and DalcA to support its clinical trials totaling $9.4 million and the payment obligations remaining at March 31, 2019 was $4.6 million.

Related Parties

Related Parties	3 Months Ended
	Mar. 31, 2019
Related Party Transactions [Abstract]
Related Parties	11. Related Parties On October 24, 2017 the Company announced a strategic research collaboration with Mosaic Biosciences, Inc. (“Mosaic”) to develop intravitreal anti-complement factor 3 products for the treatment of dry age-related macular degeneration and other retinal diseases. According to the agreement the Company and Mosaic will co-fund the research. Dr. Usman, our Chief Executive Officer and a member of our board of directors, and Mr. Lawlor, the chairman of our board of directors, were also members of the board of directors of Mosaic when this agreement was entered in to, and the agreement was reviewed by disinterested members of our board of directors and approved by our audit committee. Expenses related to the collaboration were $0.3 and $0.2 million for the three months ended March 31, 2019 and 2018, respectively.

Interest and Other Income

Interest and Other Income	3 Months Ended
	Mar. 31, 2019
Other Income And Expenses [Abstract]
Interest and Other Income	12. Interest and Other Income The following table shows the detail of interest and other income/(expense), net for the three-month periods ended March 31, 2019 and 2018 ( in thousands Three Months Ended March 31, 2019 2018 Interest income $ 631 $ 285 Loss on disposal of fixed assets — (116 ) Other income, net — 1,468 Total other income/(expense), net $ 631 $ 1,637 Other income of $1.5 million for the three months ended March 31, 2018, reflects milestone payments received under an agreement associated with neuronal nicotinic receptor assets sold in 2016.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The Company’s condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) and following the requirements of the Securities and Exchange Commission (the “SEC”) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. These financial statements have been prepared on the same basis as the Company’s annual financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments, which are necessary for a fair presentation of the Company’s financial information. These interim results and cash flows for any interim period are not necessarily indicative of the results to be expected for the full year. The accompanying condensed consolidated financial statements and related financial information should be read in conjunction with the consolidated financial statements filed with the Company’s Annual Report on Form 10-K for the year ended December 31, 2018 (“Annual Report”).
Accounting Pronouncements Recently Adopted	Accounting Pronouncements Recently Adopted The Company’s significant accounting policies are included in “Part II - Item 8 - Financial Statements and Supplementary Data - Note 3 – Summary of Significant Accounting Policies” in the Company’s Annual Report. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), to enhance the transparency and comparability of financial reporting related to leasing arrangements. The Company adopted the standard effective January 1, 2019. As discussed in our Annual Report, the Company adopted the new lease standards in the first quarter of 2019. There have been no other significant changes to these accounting policies during the first three months of 2019. At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present. Operating lease liabilities and their corresponding right-of-use assets are recorded based on the present value of lease payments over the expected lease term. The interest rate implicit in lease contracts is typically not readily determinable. As such, the Company utilizes its incremental borrowing rate, which is the rate incurred to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment. Certain adjustments to the right-of-use asset may be required for items such as initial direct costs paid or incentives received. The Company has elected to combine lease and non-lease components as a single component. The lease expense is recognized over the expected term on a straight-line basis. Operating leases are recognized on the balance sheet as right-of-use assets, operating lease liabilities, current and operating lease liabilities, non-current. As a result, the Company no longer recognizes deferred rent on the balance sheet. On January 1, 2019, the Company adopted the new lease accounting standard using the optional transition method under which comparative financial information is not restated and continues to apply the provisions of the previous lease accounting standard in its financial disclosures for the comparative periods. The Company also elected relevant optional practical expedients including 1) did not reassess whether expired or existing contracts are or contain a lease, 2) did not reassess the lease classifications or reassess the initial direct costs associated with expired or existing leases, and 3) did not separate lease and non-lease components of its operating leases in which it is the lessee. The adoption of the new lease accounting standard had an impact of approximately $2.1 million on the Company's assets and liabilities and had no impact on cash provided by or used in operating, investing or financing activities on the Company's condensed consolidated statements of cash flows. The adoption of the new lease accounting standard did not impact previously reported financial results.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Fair Value on a Recurring Basis	There were no transfers in or out of Level 1 or 2 during the periods presented. The following tables present the fair value hierarchy for assets and liabilities measured at fair value on a recurring basis as of March 31, 2019 and December 31, 2018 ( in thousands March 31, 2019 Level 1 Level 2 Level 3 Total Financial assets: Money market funds ( 1) $ 23,475 $ — $ — $ 23,475 U.S. government agency securities ( 2) 65,653 — 65,653 Federal agency securities ( 2) — 14,600 — 14,600 Restricted cash (money market funds) 50 — — 50 Total financial assets $ 89,178 $ 14,600 $ — $ 103,778 (1) Included in cash and cash equivalents on accompanying condensed consolidated balance sheets. ( 2 ) Included in short-term investments on accompanying condensed consolidated balance sheets and are classified as available-for-sale securities. December 31, 2018 Level 1 Level 2 Level 3 Total Financial assets: Money market funds ( 1) $ 29,090 $ — $ — $ 29,090 Federal agency securities ( 1) — 999 — 999 U.S. Treasury securities ( 2) 74,139 74,139 Federal agency securities ( 2) 14,775 — 14,775 Restricted cash (money market funds) 50 — — 50 Total financial assets $ 103,279 $ 15,774 $ — $ 119,053 (1) Included in cash and cash equivalents on accompanying condensed consolidated balance sheets. ( 2 ) Included in short-term investments on accompanying condensed consolidated balance sheets and are classified as available-for-sale securities.

Financial Instruments (Tables)

Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2019
Investments All Other Investments [Abstract]
Cash Equivalents, Restricted Cash and Short-Term Investments Classified as Available-for-sale Securities	Cash equivalents, restricted cash and short-term investments (debt securities) which are classified as available-for-sale securities, consisted of the following ( in thousands March 31, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Money market funds (cash equivalents) $ 23,475 $ — $ — $ 23,475 U.S. government agency securities 65,645 9 (1 ) 65,653 Federal agency securities 14,595 5 — 14,600 Restricted cash (money market funds) 50 — — 50 Total financial assets $ 103,765 $ 14 $ (1 ) $ 103,778 Classified as: Cash and cash equivalents $ 23,475 Short-term investments 80,253 Restricted cash (money market funds) 50 $ 103,778 December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Money market funds (cash equivalents) $ 29,090 $ — $ — $ 29,090 Federal agency securities (cash equivalents) 999 — — 999 Restricted cash (money market funds) 50 — — 50 U.S. government agency securities 74,144 1 (6 ) 74,139 Agency securities 14,774 1 — 14,775 Total financial assets $ 119,057 $ 2 $ (6 ) $ 119,053 Classified as: Cash and cash equivalents $ 30,089 Short-term investments 88,914 Restricted cash (money market funds) 50 $ 119,053

Lease (Tables)

Lease (Tables)	3 Months Ended
	Mar. 31, 2019
Lessee Disclosure [Abstract]
Summary of Present Value Assumptions used in Calculating Present Value of Lease Payments	The present value assumptions used in calculating the present value of the lease payments were as follows: Weighted-average remaining lease term 4.1 years Weighted-average discount rate 6.0 %
Summary of Future Lease Payments under Non-cancelable Leases	Future lease payments under non-cancelable leases as of March 31, 2019 were as follows: Remaining in 2019 $ 423 2020 578 2021 596 2022 613 2023 209 Total future minimum lease payments 2,419 Less imputed interest (283 ) Total lease liability $ 2,136

Stock Based Compensation (Table

Stock Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Option Activity Under Company's Equity Incentive Plans	The following table summarizes stock option activity under the Company’s equity incentive plans and related information: Number of Shares Underlying Outstanding Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (Years) Outstanding — December 31, 2018 1,361,977 $ 12.04 8.71 Options granted 309,300 $ 8.12 Options exercised (12,794 ) $ 4.60 Options forfeited (39,971 ) $ 7.60 Options Expired (5,641 ) $ 91.79 Outstanding — March 31, 2019 1,612,871 $ 11.17 8.77 Exercisable — March 31, 2019 468,193 $ 16.19 8.03 Vested and expected to vest — March 31, 2019 1,612,871 $ 11.17 8.77
Summary of Weighted Average Valuation Assumptions Used to Estimate Fair Value of Employee Stock Options	The fair value of employee stock options was estimated using the following weighted-average assumptions for the three months ended March 31, 2019 and 2018: Three Months Ended March 31, 2019 2018 Employee Stock Options: Risk-free interest rate 2.56 % 2.40 % Expected term (in years) 6.03 6.01 Dividend yield — — Volatility 82.91 % 109.32 % Weighted-average fair value of stock options granted $ 5.80 $ 12.34
Summary of Stock-Based Compensation Recognized	Total stock-based compensation recognized was as follows ( in thousands Three Months Ended March 31, 2019 2018 Research and development $ 238 $ 115 General and administrative ( 1) 591 491 Total stock-based compensation $ 829 $ 606 (1) 2018 includes $0.1 million in modification stock-based compensation expense related to a Board member’s departure.

Net Loss per Share Attributab_2

Net Loss per Share Attributable to Common Stockholders (Tables)	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Basic and Diluted Net Loss Per Common Share	The following table sets forth the computation of the basic and diluted net loss per common share during the three months ended March 31, 2019 and 2018 ( in thousands, except share and per share data Three Months Ended March 31, 2019 2018 Net loss attributable to common stockholders $ (15,083 ) $ (5,042 ) Weighted-average number of shares used in computing net loss per share, basic and diluted 11,963,586 8,989,669 Net loss available for common stockholders per share, basic and diluted $ (1.26 ) $ (0.56 )
Anti-dilutive Security not Included In Diluted per Share Calculations	Since the Company was in a loss position for all periods presented, diluted net loss per share is the same as basic net loss per share for all periods as the inclusion of all potential common shares outstanding would have been anti-dilutive. Potentially dilutive securities on an as-if converted basis that were not included in the diluted per share calculations because they would be anti-dilutive were as follows: Three Months Ended March 31, 2019 2018 Options to purchase common stock 1,612,871 1,026,393 Common stock warrants 10,194 12,039 Redeemable convertible notes — — Total 1,623,065 1,038,432

Interest and Other Income (Tabl

Interest and Other Income (Tables)	3 Months Ended
	Mar. 31, 2019
Other Income And Expenses [Abstract]
Detail of Interest and Other Income/(Expense), Net	The following table shows the detail of interest and other income/(expense), net for the three-month periods ended March 31, 2019 and 2018 ( in thousands Three Months Ended March 31, 2019 2018 Interest income $ 631 $ 285 Loss on disposal of fixed assets — (116 ) Other income, net — 1,468 Total other income/(expense), net $ 631 $ 1,637

Nature of Operations - Addition

Nature of Operations - Additional Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)Segment	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)
Accounting Policies [Abstract]
Number of operating segment | Segment	1
Net loss	$ 15,083	$ 5,042
Accumulated deficit	218,425		$ 203,342
Cash, cash equivalents, and short-term investments	$ 105,300

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Accounting Standards Update 2016-02 Leases (Topic 842)
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Impact of new lease accounting standard on assets and liabilities	$ 2.1

Assets and Liabilities Measured

Assets and Liabilities Measured at Fair Value (Detail) - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value		$ 103,778	$ 119,053
Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	[1]	23,475	29,090
Restricted cash (money market funds)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value		50	50
U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	[2]	65,653
Federal Agency Securities | Short-Term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	[2]	14,600	14,775
Federal Agency Securities | Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	[1]		999
US Treasury Securities | Short-Term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	[2]		74,139
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value		89,178	103,279
Fair Value, Inputs, Level 1 | Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	[1]	23,475	29,090
Fair Value, Inputs, Level 1 | Restricted cash (money market funds)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value		50	50
Fair Value, Inputs, Level 1 | U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	[2]	65,653
Fair Value, Inputs, Level 1 | US Treasury Securities | Short-Term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	[2]		74,139
Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value		14,600	15,774
Fair Value, Inputs, Level 2 | Federal Agency Securities | Short-Term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	[2]	$ 14,600	14,775
Fair Value, Inputs, Level 2 | Federal Agency Securities | Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	[1]		$ 999
[1]	Included in cash and cash equivalents on accompanying condensed consolidated balance sheets.
[2]	Included in short-term investments on accompanying condensed consolidated balance sheets and are classified as available-for-sale securities.

Cash Equivalents, Restricted Ca

Cash Equivalents, Restricted Cash and Short-Term Investments Classified as Available-for-sale Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 103,765	$ 119,057
Gross Unrealized Gains	14	2
Gross Unrealized Losses	(1)	(6)
Estimated Fair Value	103,778	119,053
Money Market Funds | Cash Equivalents
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	23,475	29,090
Estimated Fair Value	23,475	29,090
Money Market Funds | Restricted cash
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	50	50
Estimated Fair Value	50	50
U.S. Government Agency Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	65,645	74,144
Gross Unrealized Gains	9	1
Gross Unrealized Losses	(1)	(6)
Estimated Fair Value	65,653	74,139
Cash and Cash Equivalents
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	23,475	30,089
Short-Term Investments
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	80,253	88,914
Federal Agency Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	14,595
Gross Unrealized Gains	5
Estimated Fair Value	$ 14,600
Federal Agency Securities | Cash Equivalents
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		999
Estimated Fair Value		999
Agency Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		14,774
Gross Unrealized Gains		1
Estimated Fair Value		$ 14,775

Financial Instruments - Additio

Financial Instruments - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2019USD ($)
Financial Instrument [Line Items]
Material realized gains or losses on available-for-sale securities	$ 0
Maximum
Financial Instrument [Line Items]
Available for sale securities contractual maturities	1 year

Lease - Additional Information

Lease - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Lessee Disclosure [Abstract]
Lease expiration date	Apr. 30, 2023
Lessee operating lease renewal term description	no stated renewal options
Operating lease expense	$ 0.2

Summary of Present Value Assump

Summary of Present Value Assumptions used in Calculating Present Value of Lease Payments (Detail)	Mar. 31, 2019
Lessee Disclosure [Abstract]
Weighted-average remaining lease term	4 years 1 month 6 days
Weighted-average discount rate	6.00%

Summary of Future Lease Payment

Summary of Future Lease Payments under Non-cancelable Leases (Detail)	Mar. 31, 2019USD ($)
Operating Lease Liabilities Payments Due [Abstract]
Remaining in 2019	$ 423
2020	578
2021	596
2022	613
2023	209
Total future minimum lease payments	2,419
Less imputed interest	(283)
Total lease liability	$ 2,136

Summary of Option Activity Unde

Summary of Option Activity Under Company's Equity Incentive Plans (Detail) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Number of Shares Underlying Outstanding Options
Number of Shares Underlying Outstanding Options, Beginning Balance	1,361,977
Number of Shares Underlying Outstanding Options, Options granted	309,300
Number of Shares Underlying Outstanding Options, Options exercised	(12,794)
Number of Shares Underlying Outstanding Options, Options forfeited	(39,971)
Number of Shares Underlying Outstanding Options, Options Expired	(5,641)
Number of Shares Underlying Outstanding Options, Ending Balance	1,612,871	1,361,977
Number of Shares Underlying Outstanding Options, Exercisable - March 31, 2019	468,193
Number of Shares Underlying Outstanding Options, Vested and expected to vest - March 31, 2019	1,612,871
Weighted- Average Exercise Price
Weighted- Average Exercise Price, Beginning Balance	$ 12.04
Weighted- Average Exercise Price, Options granted	8.12
Weighted- Average Exercise Price, Options exercised	4.60
Weighted- Average Exercise Price, Options forfeited	7.60
Weighted- Average Exercise Price, Options Expired	91.79
Weighted- Average Exercise Price, Ending Balance	11.17	$ 12.04
Weighted- Average Exercise Price, Exercisable - March 31, 2019	16.19
Weighted- Average Exercise Price, Vested and expected to vest - March 31, 2019	$ 11.17
Weighted-Average Remaining Contractual Term (Years)
Weighted-Average Remaining Contractual Term (Years), Outstanding Balance	8 years 9 months 7 days	8 years 8 months 15 days
Weighted-Average Remaining Contractual Term (Years), Exercisable - March 31, 2019	8 years 10 days
Weighted-Average Remaining Contractual Term (Years), Vested and expected to vest - March 31, 2019	8 years 9 months 7 days

Stock Based Compensation - Addi

Stock Based Compensation - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock available for future grant	1,031,456
Shares remaining outstanding	1,612,871
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term of stock options	6 years 10 days	6 years 3 days
Unrecognized employee stock based compensation expense	$ 7.4
Unrecognized employee stock based compensation expense, period for recognition	2 years 11 months 4 days

Fair Values of Stock Options Es

Fair Values of Stock Options Estimated Using Black-Scholes Valuation Model (Detail) - Employee Stock Option - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Black Scholes Method Used [Line Items]
Risk-free interest rate	2.56%	2.40%
Expected term (in years)	6 years 10 days	6 years 3 days
Dividend yield	0.00%	0.00%
Volatility	82.91%	109.32%
Weighted-average fair value of stock options granted	$ 5.80	$ 12.34

Summary of Stock-Based Compensa

Summary of Stock-Based Compensation Recognized (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation		$ 829	$ 606
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation		238	115
General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	[1]	$ 591	$ 491
[1]	2018 includes $0.1 million in modification stock-based compensation expense related to a Board member’s departure.

Summary of Stock-Based Compen_2

Summary of Stock-Based Compensation Recognized (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 829	$ 606
Board Member's Departure
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense		$ 100

Collaborations - Additional Inf

Collaborations - Additional Information (Detail) - USD ($)	1 Months Ended		3 Months Ended
	Dec. 31, 2018	Feb. 28, 2018	Mar. 31, 2019	Dec. 08, 2016
Pfizer Inc | Collaboration Agreement
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Milestone payment		$ 1,000,000	$ 0
Pfizer Inc | Collaboration Agreement | Maximum
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Contingent cash payments upon achievement of clinical, regulatory and commercial milestones				$ 17,500,000
ISU Abxis | Amended and Restated License Agreement
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Regulatory and development milestone payment	$ 2,500,000
ISU Abxis | Amended and Restated License Agreement | Maximum
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Milestone payment	19,500,000
Commercial milestone payments	$ 17,000,000

Basic and Diluted Net Loss Per

Basic and Diluted Net Loss Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share [Abstract]
Net loss attributable to common stockholders	$ (15,083)	$ (5,042)
Weighted-average number of shares used in computing net loss per share, basic and diluted	11,963,586	8,989,669
Net loss available for common stockholders per share, basic and diluted	$ (1.26)	$ (0.56)

Anti-dilutive Security not Incl

Anti-dilutive Security not Included In Diluted per Share Calculations (Detail) - shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti dilutive securities	1,623,065	1,038,432
Options To Purchase Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti dilutive securities	1,612,871	1,026,393
Common Stock Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti dilutive securities	10,194	12,039

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	Feb. 15, 2018	Feb. 13, 2018	Mar. 31, 2018
Stockholders Equity Disclosure [Line Items]
Net proceeds from sale of common stock	$ 106.8
Common Stock
Stockholders Equity Disclosure [Line Items]
Firm commitment underwritten public offering shares		2,941,176
Issuance of stock, shares	3,382,352		3,382,352
Common stock price, per share	$ 34
Common Stock | Overallotment Option
Stockholders Equity Disclosure [Line Items]
Issuance of stock, shares	441,176

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - AGC Biologics, Inc - Marzeptacog Alfa Activated and Dalcinonacog Alfa $ in Millions	Mar. 31, 2019USD ($)
Commitments And Contingencies Disclosure [Line Items]
Clinical trials	$ 9.4
Contractual obligation payments	$ 4.6

Related Parties - Additional In

Related Parties - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Mosaic | Strategic Research Collaboration to Develop Intravitreal Anti-Complement Factor 3 Products
Related Party Transaction [Line Items]
Expenses related to collaboration	$ 0.3	$ 0.2

Detail of Interest and Other In

Detail of Interest and Other Income/(Expense), Net (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Other Income And Expenses [Abstract]
Interest income	$ 631	$ 285
Loss on disposal of fixed assets		(116)
Other income, net		1,468
Total other income/(expense), net	$ 631	$ 1,637

Interest and Other Income - Add

Interest and Other Income - Additional Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Other Income And Expenses [Abstract]
Other income reflects milestone payments received	$ 1,468