Global Blood Therapeutics (GBT) 10-Q 6 May 20 2020 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Mar. 31, 2020	May 01, 2020
Cover [Abstract]
Document Type	10-Q
Document Period End Date	Mar. 31, 2020
Entity Registrant Name	Global Blood Therapeutics, Inc.
Entity Filer Category	Large Accelerated Filer
Trading Symbol	GBT
Entity Emerging Growth Company	false
Entity Small Business	false
Document Transition Report	false
Entity Common Stock, Shares Outstanding		60,940,277
Document Quarterly Report	true
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Entity File Number	001-37539
Entity Tax Identification Number	27-4825712
Entity Shell Company	false
Entity Address, Address Line One	181 Oyster Point Boulevard
Entity Address, City or Town	South San Francisco
Entity Address, State or Province	CA
City Area Code	650
Local Phone Number	741-7700
Entity Address, Postal Zip Code	94080
Title of 12(b) Security	Common Stock
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001629137
Current Fiscal Year End Date	--12-31

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 315,525	$ 302,237
Short-term marketable securities	215,295	307,732
Accounts receivable, net	4,578	2,637
Inventories	14,927	1,277
Prepaid expenses and other current assets	14,144	14,114
Total current assets	564,469	627,997
Property and equipment, net	37,329	27,113
Long-term marketable securities	84,378	85,030
Operating lease right-of-use assets	52,082	52,775
Restricted cash	2,395	2,395
Other assets, noncurrent	493	789
Total assets	741,146	796,099
Current liabilities:
Accounts payable	13,696	10,621
Accrued liabilities	34,562	41,358
Accrued compensation	11,269	17,578
Other liabilities, current	2,721	1,896
Total current liabilities	62,248	71,453
Long-term debt	73,688	73,559
Operating lease liabilities, noncurrent	81,638	72,359
Other liabilities, noncurrent		34
Total liabilities	217,574	217,405
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.001 par value, 5,000,000 shares authorized as of March 31, 2020 (unaudited) and December 31, 2019; no shares issued and outstanding
Common stock, $0.001 par value, 150,000,000 shares authorized as of March 31, 2020 (unaudited) and December 31, 2019, respectively; 60,886,371 and 60,644,380 shares issued and outstanding as of March 31, 2020 (unaudited) and December 31, 2019, respectively	61	61
Additional paid-in capital	1,334,238	1,316,795
Accumulated other comprehensive income	1,215	754
Accumulated deficit	(811,942)	(738,916)
Total stockholders' equity	523,572	578,694
Total liabilities and stockholders' equity	$ 741,146	$ 796,099

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2020	Dec. 31, 2019
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	150,000,000	150,000,000
Common stock, shares issued	60,886,371	60,644,380
Common stock, shares outstanding	60,886,371	60,644,380

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenues [Abstract]
Product sales, net	$ 14,118
Costs and operating expenses:
Cost of sales	135
Research and development	39,773	$ 34,468
Selling, general and administrative	47,662	18,055
Total costs and operating expenses	87,570	52,523
Loss from operations	(73,452)	(52,523)
Other income (expense):
Interest income	2,856	3,831
Interest expenses	(2,314)	(181)
Other expenses, net	(116)	(50)
Total other income, net	426	3,600
Net loss	(73,026)	(48,923)
Other comprehensive income:
Net unrealized gain on marketable securities, net of tax	461	624
Comprehensive loss	$ (72,565)	$ (48,299)
Basic and diluted net loss per common share	$ (1.20)	$ (0.87)
Weighted-average number of shares used in computing basic and diluted net loss per common share	60,787,710	56,231,587

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income [Member]	Accumulated Deficit [Member]
Beginning Balance at Dec. 31, 2018	$ 572,799	$ 56	$ 1,044,941	$ (48)	$ (472,150)
Beginning Balance, Shares at Dec. 31, 2018		55,640,299
Issuance of common stock upon equity offerings, net of issuance costs	21,246		21,246
Issuance of common stock upon equity offerings, net of issuance costs, Shares		511,363
Issuance of common stock upon exercise of stock options	817		817
Issuance of common stock upon exercise of stock options, Shares		52,288
Issuance of common stock upon vesting of restricted share units, net of shares withheld for employee taxes	(686)		(686)
Issuance of common stock upon vesting of restricted share units, net of shares withheld for employee taxes, Shares		78,155
Issuance of common stock pursuant to ESPP purchases	1,128		1,128
Issuance of common stock pursuant to ESPP purchases, Shares		30,745
Vesting of restricted stock purchases	80		80
Vesting of restricted stock purchases, Shares		24,195
Stock-based compensation expense	9,453		9,453
Net unrealized gain on marketable securities	624			624
Net loss	(48,923)				(48,923)
Ending Balance at Mar. 31, 2019	556,538	$ 56	1,076,979	576	(521,073)
Ending Balance, Shares at Mar. 31, 2019		56,337,045
Beginning Balance at Dec. 31, 2019	578,694	$ 61	1,316,795	754	(738,916)
Beginning Balance, Shares at Dec. 31, 2019		60,644,380
Issuance of common stock upon exercise of stock options	$ 967		967
Issuance of common stock upon exercise of stock options, Shares	33,937	33,937
Issuance of common stock upon vesting of restricted share units, net of shares withheld for employee taxes	$ (2,099)		(2,099)
Issuance of common stock upon vesting of restricted share units, net of shares withheld for employee taxes, Shares		160,594
Issuance of common stock pursuant to ESPP purchases	1,870		1,870
Issuance of common stock pursuant to ESPP purchases, Shares		47,460
Stock-based compensation expense	16,705		16,705
Net unrealized gain on marketable securities	461			461
Net loss	(73,026)				(73,026)
Ending Balance at Mar. 31, 2020	$ 523,572	$ 61	$ 1,334,238	$ 1,215	$ (811,942)
Ending Balance, Shares at Mar. 31, 2020		60,886,371

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (73,026)	$ (48,923)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,238	2,094
Amortization (accretion) of premium (discount) on marketable securities	(101)	(565)
Non-cash interest expense	412
Amortization of operating lease right-of-use assets	693	100
Stock-based compensation	16,367	9,453
Changes in operating assets and liabilities:
Accounts receivables	(1,941)
Inventories	(13,218)
Prepaid expenses and other assets	(147)	49
Accounts payable	2,567	1,272
Accrued liabilities	(6,766)	887
Accrued compensation	(6,309)	(4,407)
Operating lease liabilities	1,762	(276)
Other liabilities	(1,153)	0
Net cash used in operating activities	(78,622)	(40,316)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment	(2,524)	(56)
Purchase of marketable securities	(57,936)	(164,177)
Maturities of marketable securities	151,586	63,582
Net cash provided by (used in) investing activities	91,126	(100,651)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock in public offering, net		21,207
Proceeds from issuance of common stock in settlement of employee stock purchase plan and exercise of stock options	2,968	1,925
Payments of debt issuance costs	(85)
Tax paid related to net share settlement of equity awards	(2,099)	(686)
Net cash provided by financing activities	784	22,446
Net increase (decrease) in cash, cash equivalents and restricted cash	13,288	(118,521)
Cash, cash equivalents and restricted cash at beginning of period	304,632	277,752
Cash, cash equivalents and restricted cash at end of period	317,920	159,231
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING INFORMATION:
Leasehold improvements paid for by landlord	9,461
Accrued purchase of property and equipment	563	146
Accrued issuance costs	$ (85)	$ (41)

Organization and Basis of Prese

Organization and Basis of Presentation	3 Months Ended
	Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	1. Organization and Basis of Presentation Global Blood Therapeutics , ® Need for Additional Capital In the course of our development activities, we have sustained operating losses and we expect such losses to continue over the next several years. Our ultimate success depends on the outcome of our commercial launch of Oxbryta, research and development and business development activities. Since inception through March 31, 2020, we have incurred cumulative net losses of $811.9 million. We expect to incur additional losses for the foreseeable future to commercialize Oxbryta and conduct product research and development, and expect to potentially raise additional capital to fully implement our business plan. If needed, we intend to raise such capital through borrowings, the issuance of additional equity, and potentially through strategic alliances with partner companies or other transactions. However, if such financing is not available at adequate levels, we will need to re-evaluate

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Preparation The accompanying unaudited interim condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America, or U.S. GAAP, and applicable rules and regulations of the Securities and Exchange Commission, or SEC, regarding interim financial reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP have been condensed or omitted, and accordingly the balance sheet as of December 31, 2019 has been derived from audited consolidated financial statements at that date but does not include all of the information required by U.S. GAAP for complete financial statements. These unaudited interim condensed consolidated financial statements have been prepared on the same basis as our annual consolidated financial statements and, in the opinion of management, reflect all adjustments (consisting only of normal recurring adjustments) that are necessary for a fair presentation of our financial information. The results of operations for the three months ended March 31, 2020 are not necessarily indicative of the results to be expected for the year ending December 31, 2020 or for any other interim period or for any other future year. The accompanying unaudited interim condensed consolidated financial statements and related financial information should be read in conjunction with the audited financial statements and the related notes thereto for the year ended December 31, 2019 included in our Annual Report on Form 10-K, Use of Estimates The preparation of the accompanying consolidated financial statements in accordance with U.S. GAAP requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of revenues Principles of Consolidation The accompanying unaudited interim condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated upon consolidation. Significant Accounting Policies Except as noted below, there have been no material revisions in our significant accounting policies described in Note 2 to the consolidated financial statements included in our Annual Report on Form 10-K Accounting Pronouncements Adopted In August 2018, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update, or ASU, No. 2018-15, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40), Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract 2018-15. 2018-15 internal-use 350-40 2018-15 In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820) 2018-13 2018-13. 2018-13 In June 2016, the FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments (Topic 326) Available-for-sale available-for-sale 2016-13 prospectively.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements Fair value accounting is applied for all financial assets and liabilities that are recognized or disclosed at fair value in the consolidated financial statements on a recurring basis (at least annually). Our financial instruments consist of cash and cash equivalents, marketable securities, accounts receivables, accounts payable and accrued liabilities. Cash and cash equivalents, marketable securities and restricted cash are reported at their respective fair values on our condensed consolidated balance sheets. The remaining financial instruments are reported on our condensed consolidated balance sheets at cost that approximate current fair values due to their relatively short maturities. Assets and liabilities recorded at fair value on a recurring basis in the condensed consolidated balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The authoritative guidance on fair value measurements establishes a three-tier fair value hierarchy for disclosure of fair value measurements as follows: Level 1 Level 2 Level 3 en es The following table summarizes our financial assets measured at fair value on a recurring basis (in thousands): March 31, 2020 Total Level 1 Level 2 Level 3 Financial Assets: Money market funds $ 294,863 $ 294,863 $ — $ Corporate debt securities 118,390 — 118,390 — U.S. government agency securities 79,579 — 79,579 — Certificates of deposits 5,808 — 5,808 — U.S. government securities 95,896 — 95,896 — Total financial assets $ 594,536 $ 294,863 $ 299,673 $ — December 31, 2019 Total Level 1 Level 2 Level 3 Financial Assets: Money market funds $ 250,535 $ 250,535 $ — $ Corporate debt securities 152,149 — 152,149 — U.S. government agency securities 95,032 — 95,032 — Certificates of deposits 6,282 — 6,282 — U.S. government securities 140,244 — 140,244 — Total financial assets $ 644,242 $ 250,535 $ 393,707 $ — We estimate the fair valu es two-sided A-1/P-1 nd

Available-for-Sale Securities

Available-for-Sale Securities	3 Months Ended
	Mar. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Available-for-Sale Securities	4. Available-for-Sale Estimated fair values of available-for-sale March 31, 2020 December 31, 2019 Amortized Cost Unrealized Gains Unrealized (Losses) Estimated Fair Value Amortized Cost Unrealized Gains Unrealized (Losses) Estimated Fair Value Financial Assets: Money market funds $ 294,863 $ — $ — $ 294,863 $ 250,535 $ — $ — $ 250,535 Corporate debt securities 118,187 287 (84 ) 118,390 151,773 384 (8 ) 152,149 U.S. government agency securities 79,417 181 (19 ) 79,579 94,963 73 (4 ) 95,032 Certificates of deposits 5,766 42 — 5,808 6,239 43 — 6,282 U.S. government securities 95,088 808 — 95,896 139,978 266 — 140,244 Total $ 593,321 $ 1,318 $ (103 ) $ 594,536 $ 643,488 $ 766 $ (12 ) $ 644,242 The following table summarizes the classification of the available-for-sale March 31, 2020 December 31, 2019 Cash and cash equivalents $ 294,863 $ 251,480 Short-term marketable securities 215,295 307,732 Long-term marketable securities 84,378 85,030 Total $ 594,536 $ 644,242 We do not intend to sell the investments that are in an unrealized loss position, and it is unlikely that we will be required to sell the investments before recovery of their amortized cost basis, which may be maturity. We have determined that the gross unrealized losses on our marketable securities were temporary in nature during the periods presented.

Balance Sheet Components

Balance Sheet Components	3 Months Ended
	Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Balance Sheet Components	5. Balance Sheet Components Inventories We began capitalizing inventories in November 2019 once the FDA approved Oxbryta. Inventories consist of the following (in thousands): March 31, 2020 December 31, 2019 Raw materials $ 7,141 $ 700 Work-in-process 7,217 525 Finished goods 569 52 Total inventories $ 14,927 $ 1,277 Property and Equipment Property and equipment consists of the following (in thousands): March 31, 2020 December 31, 2019 Laboratory equipment $ 8,472 $ 8,314 Computer equipment 2,224 2,224 Leasehold improvements 13,785 13,785 Construction-in-progress 31,679 19,289 Total property and equipment 56,160 43,612 Less: accumulated depreciation and amortization (18,831 ) (16,499 ) Property and equipment, net $ 37,329 $ 27,113 Accrued liabilities Accrued liabilities consist of the following (in thousands): March 31, 2020 December 31, 2019 Accrued research and development costs $ 9,659 $ 26,480 Accrued manufacturing costs 18,160 9,466 Accrued professional and consulting services 4,262 4,564 Accrued sales deductions 1,998 529 Other 483 319 Total accrued liabilities $ 34,562 $ 41,358 Other liabilities, current Other liabilities consist of the following (in thousands): March 31, 2020 December 31, 2019 Operating lease liabilities, current $ 2,691 $ 1,866 Other payable 30 30 Total other liabilities, current $ 2,721 $ 1,896

Long-term Debt

Long-term Debt	3 Months Ended
	Mar. 31, 2020
Disclosure Text Block [Abstract]
Long-term Debt	6. Long-term Debt Term Loan On December 17, 2019, we entered into the Loan Agreement, or Term Loan, with funds managed by Pharmakon Advisors LP, which are BioPharma Credit PLC, as collateral agent and a lender, and Biopharma Credit Investments V (Master) LP, as a lender, and collectively, the Lenders, for a senior secured credit facility consisting of an initial tranche of $75.0 million and the option to draw an additional $75.0 million until December 31, 2020. The first tranche, in the amount of $75.0 million, was funded in connection with the closing date of the Term Loan in December 2019. The Term Loan carries a 72-month 3-month We have the option to prepay all or a portion of the borrowed amounts under the Term Loan. If we exercise this option, we must pay a prepayment fee between 1% and 3% of the principal amount being prepaid depending on the timing of the prepayment, or Prepayment Fee. If the prepayment occurs before December 2022, we must also pay an amount equal to the sum of all interest that would have accrued and been payable from date of prepayment through December 2022, or Make Whole Amount. We are obligated to pay an additional fee to the Lenders determined by multiplying the principal amount being paid or prepaid multiplied by 2%, or Paydown Fee, when such payments are made. In the event of default or change in control, all unpaid principal and all accrued and unpaid interest amounts (if any) become immediately due and payable, at which point, we will be subject to the Prepayment Fee, the Make Whole Amount (if any) and the Paydown Fee. Events of default include, but are not limited to, a payment default, a material adverse change, and insolvency. The obligations under the Term Loan are secured by a first priority security interest in and a lien on substantially all of our assets, subject to certain exceptions. Debt issuance costs paid directly to the Lenders of $1.1 million and the other debt issuance costs of $0.4 million were accounted for s Future payments of principal and interest on the Term Loan as of March 31, 2020 were as follows (in thousands): Year ending December 31, Amount 2020 (nine months) $ 5,063 2021 6,750 2022 6,750 2023 31,406 2024 29,156 2025 26,906 Total minimum payments 106,031 Less amount representing interest (29,531 ) Less amount representing Paydown Fee (1,500 ) Long-term debt, gross 75,000 Discount on notes payable (1,418 ) Accretion of Paydown Fee 106 Long-term debt $ 73,688

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. Commitments and Contingencies Leases We have operating leases for our headquarters, where we have office and research and development laboratory facilities, and equipment. Our leases have remaining lease terms of 1 to 10 years. Most of these leases require monthly lease payments that may be subject to annual increases throughout the lease term. Certain of these leases include renewal options at our election, with renewal terms that can extend the lease term from 1 to 10 years. These optional periods have not been considered in the determination of the right-of-use, Lease costs included in operating expenses in the consolidated statement of operations in relation to these operating leases were $3.1 million and $1.9 million for the three months ended March 31, 2020 and 2019, respectively. Included in these lease costs were variable lease cost s, which were non-lease Supplemental cash flow information related to leases for the period reported is as follows (in thousands, except weighted-average remaining lease term and weighted-average discount rate): Three Months Ended March 31, 2020 2019 ROU assets obtained in exchange for new operating lease upon adoption of ASC 842 $ — $ 14,177 Cash paid for amounts included in the measurement of lease liabilities 1,153 1,117 Weighted-average remaining lease term of operating leases (in years) 10 8.7 Weighted-average discount rate of operating leases 8.7 % 13.2 % The majority of our lease costs are driven by our operating lease for our headquarters in South San Francisco, where we have office and research and development laboratory facilities. In March 2017, we entered into a noncancelable operating lease, or Existing Lease, for approximately 67,185 square feet of space in South San Francisco, California, or Existing Premises. The Existing Lease term commenced in November 2017 as we gained control over physical access to the Existing Premises. We have acquired $11.1 million of leasehold improvements at the Existing Premises with the tenant inducement allowance provided under the Existing Lease. We are required to repay $1.7 million of the tenant inducement allowance to the landlord in the form of additional monthly rent with interest applied over the term of the Existing Lease. In August 2018, we entered into an amendment to the Existing Lease, or Lease Amendment, to relocate the leased premises from the Existing Premises to a to-be-constructed . The date on which we became responsible for paying rent under the Lease Amendment was March 13, 2020, the 10-year 10-year On October 1, 2019, we determined that the Lease Amendment for the Substitute Premises had commenced as we had the right to control the Substitute Premises. construction-in-progress We intend to vacate the Existing Premises and surrender and deliver the Existing Premises to the landlord on or before June 1, 2020, upon which time we will have no further obligations with respect to the Existing Premises. Upon signing of the Lease Amendment, we re-evaluated As of March 31, 2020, the maturities of our operating lease liabilities were as follows (in thousands): Year ending December 31, Amount 2020 (nine months) $ 5,878 (a) 2021 11,736 2022 12,116 2023 12,508 2024 12,913 2025 13,333 Thereafter 61,035 Total lease payments 129,519 Less: Imputed interest (b) (45,190 ) Present value of operating lease liabilities $ 84,329 (a) Includes our lease payments of $7.1 million, which is partially offset by the expected receipt of the remaining tenant inducements of $1.2 million. Contingencies In the ordinary course of business, we may be subject to legal claims and regulatory actions that could have a material adverse effect on our business or financial position. We assess our potential liability in such situations by analyzing potential outcomes, assuming various litigation, regulatory and settlement strategies. If we determine a loss is probable and its amount can be reasonably estimated, we accrue an amount equal to the estimated loss. No losses and no provision for a loss contingency have been recorded to date.

Stock-based Compensation

Stock-based Compensation	3 Months Ended
	Mar. 31, 2020
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-based Compensation	8. Stock-Based Compensation We have three stock-based compensation plans – the Amended and Restated 2017 Inducement Equity Plan, or 2017 Inducement Plan, the 2015 Stock Option and Incentive Plan, or 2015 Plan, and the 2012 Stock Option and Grant Plan, or 2012 Plan. As of March 31, 2020, there were 755,891 shares reserved under the 2017 Inducement Plan and 4,528,603 shares reserved under the 2015 Plan for the future issuance of equity awards. Upon adoption of the 2015 Plan in July 2015, no new awards or grants are permitted under the 2012 Plan. See Note 10 to the Consolidated Financial Statements included in our Annual Report on Form 10-K Stock Options The following summarizes option activity under the 2017 Inducement Plan, 2015 Plan and 2012 Plan: Number of Weighted- Outstanding — December 31, 2019 3,573,860 $ 36.24 Options granted 621,703 66.05 Options exercised (33,937 ) 28.50 Options canceled (27,905 ) 47.16 Outstanding — March 31, 2020 4,133,721 $ 40.72 The fair values of stock options granted to employees were calculated using the following assumptions: Three Months Ended March 31, 2020 2019 Expected term (in years) 6.1 6.1 Volatility 69.6%-69.9% 71.6%-72.2% Risk-free interest rate 1.4%-1.8% 2.5%-2.6% Dividend yield — — Restricted Stock Units The following table summarizes activity of restricted stock units, or RSUs, granted to employees with service-based vesting under the 2017 Inducement Plan and 2015 Plan and related information: Number of RSUs Weighted- Average Grant Date Fair Value Non-vested 1,848,772 $ 49.19 RSUs granted 1,073,766 66.16 RSUs vested (192,966 ) 45.68 RSUs forfeited (38,413 ) 48.18 Non-vested 2,691,159 $ 56.23 Stock-Based Compensation Expense Total stock-based compensation recognized by function included in the condensed consolidated statements of operations and comprehensive loss was as follows (in thousands): Three Months Ended March 31, 20 20 2019 Research and development $ 5,350 $ 4,023 Selling, general and administrative 11,017 5,430 Total stock-based compensation expense $ 16,367 $ 9,453

Net Loss per Share

Net Loss per Share	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Net Loss per Share	9. Net Loss per Share Basic net loss per share is computed by dividing net loss by the weighted-average number of common shares outstanding for the period. Since we were 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. The following securities were not included in the diluted net loss per share calculations because their effect was anti-dilutive: Three Months Ended March 31, 2020 2019 Options to purchase common stock 4,133,721 3,813,995 Restricted stock subject to future vesting — 22,856 Restricted stock units 2,691,159 1,626,127 Total 6,824,880 5,462,978

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Preparation The accompanying unaudited interim condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America, or U.S. GAAP, and applicable rules and regulations of the Securities and Exchange Commission, or SEC, regarding interim financial reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP have been condensed or omitted, and accordingly the balance sheet as of December 31, 2019 has been derived from audited consolidated financial statements at that date but does not include all of the information required by U.S. GAAP for complete financial statements. These unaudited interim condensed consolidated financial statements have been prepared on the same basis as our annual consolidated financial statements and, in the opinion of management, reflect all adjustments (consisting only of normal recurring adjustments) that are necessary for a fair presentation of our financial information. The results of operations for the three months ended March 31, 2020 are not necessarily indicative of the results to be expected for the year ending December 31, 2020 or for any other interim period or for any other future year. The accompanying unaudited interim condensed consolidated financial statements and related financial information should be read in conjunction with the audited financial statements and the related notes thereto for the year ended December 31, 2019 included in our Annual Report on Form 10-K,
Use of Estimates	Use of Estimates The preparation of the accompanying consolidated financial statements in accordance with U.S. GAAP requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of revenues
Principles of Consolidation	Principles of Consolidation The accompanying unaudited interim condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated upon consolidation.
Significant Accounting Policies	Significant Accounting Policies Except as noted below, there have been no material revisions in our significant accounting policies described in Note 2 to the consolidated financial statements included in our Annual Report on Form 10-K
Accounting Pronouncements Adopted	Accounting Pronouncements Adopted In August 2018, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update, or ASU, No. 2018-15, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40), Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract 2018-15. 2018-15 internal-use 350-40 2018-15 In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820) 2018-13 2018-13. 2018-13 In June 2016, the FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments (Topic 326) Available-for-sale available-for-sale 2016-13 prospectively.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value, Assets Measured on Recurring Basis	The following table summarizes our financial assets measured at fair value on a recurring basis (in thousands): March 31, 2020 Total Level 1 Level 2 Level 3 Financial Assets: Money market funds $ 294,863 $ 294,863 $ — $ Corporate debt securities 118,390 — 118,390 — U.S. government agency securities 79,579 — 79,579 — Certificates of deposits 5,808 — 5,808 — U.S. government securities 95,896 — 95,896 — Total financial assets $ 594,536 $ 294,863 $ 299,673 $ — December 31, 2019 Total Level 1 Level 2 Level 3 Financial Assets: Money market funds $ 250,535 $ 250,535 $ — $ Corporate debt securities 152,149 — 152,149 — U.S. government agency securities 95,032 — 95,032 — Certificates of deposits 6,282 — 6,282 — U.S. government securities 140,244 — 140,244 — Total financial assets $ 644,242 $ 250,535 $ 393,707 $ —

Available-for-Sale Securities (

Available-for-Sale Securities (Tables)	3 Months Ended
	Mar. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Summary of Available-for-Sale Securities	The following table is a summary of available-for-sale securities recorded in cash and cash equivalents, restricted cash, or marketable securities in our condensed consolidated balance sheets (in thousands): March 31, 2020 December 31, 2019 Amortized Cost Unrealized Gains Unrealized (Losses) Estimated Fair Value Amortized Cost Unrealized Gains Unrealized (Losses) Estimated Fair Value Financial Assets: Money market funds $ 294,863 $ — $ — $ 294,863 $ 250,535 $ — $ — $ 250,535 Corporate debt securities 118,187 287 (84 ) 118,390 151,773 384 (8 ) 152,149 U.S. government agency securities 79,417 181 (19 ) 79,579 94,963 73 (4 ) 95,032 Certificates of deposits 5,766 42 — 5,808 6,239 43 — 6,282 U.S. government securities 95,088 808 — 95,896 139,978 266 — 140,244 Total $ 593,321 $ 1,318 $ (103 ) $ 594,536 $ 643,488 $ 766 $ (12 ) $ 644,242
Summary of Classification of Available-for-Sale Securities on Consolidated Balance Sheets	The following table summarizes the classification of the available-for-sale March 31, 2020 December 31, 2019 Cash and cash equivalents $ 294,863 $ 251,480 Short-term marketable securities 215,295 307,732 Long-term marketable securities 84,378 85,030 Total $ 594,536 $ 644,242

Balance Sheet Components (Table

Balance Sheet Components (Tables)	3 Months Ended
	Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Inventories	We began capitalizing inventories in November 2019 once the FDA approved Oxbryta. Inventories consist of the following (in thousands): March 31, 2020 December 31, 2019 Raw materials $ 7,141 $ 700 Work-in-process 7,217 525 Finished goods 569 52 Total inventories $ 14,927 $ 1,277
Property and Equipment	Property and Equipment Property and equipment consists of the following (in thousands): March 31, 2020 December 31, 2019 Laboratory equipment $ 8,472 $ 8,314 Computer equipment 2,224 2,224 Leasehold improvements 13,785 13,785 Construction-in-progress 31,679 19,289 Total property and equipment 56,160 43,612 Less: accumulated depreciation and amortization (18,831 ) (16,499 ) Property and equipment, net $ 37,329 $ 27,113
Accrued Liabilities	Accrued liabilities Accrued liabilities consist of the following (in thousands): March 31, 2020 December 31, 2019 Accrued research and development costs $ 9,659 $ 26,480 Accrued manufacturing costs 18,160 9,466 Accrued professional and consulting services 4,262 4,564 Accrued sales deductions 1,998 529 Other 483 319 Total accrued liabilities $ 34,562 $ 41,358
Other Liabilities	Other liabilities, current Other liabilities consist of the following (in thousands): March 31, 2020 December 31, 2019 Operating lease liabilities, current $ 2,691 $ 1,866 Other payable 30 30 Total other liabilities, current $ 2,721 $ 1,896

Long-term Debt (Table)

Long-term Debt (Table)	3 Months Ended
	Mar. 31, 2020
Text Block [Abstract]
Schedule of Future payments of principal and interest on the Term Loan	Future payments of principal and interest on the Term Loan as of March 31, 2020 were as follows (in thousands): Year ending December 31, Amount 2020 (nine months) $ 5,063 2021 6,750 2022 6,750 2023 31,406 2024 29,156 2025 26,906 Total minimum payments 106,031 Less amount representing interest (29,531 ) Less amount representing Paydown Fee (1,500 ) Long-term debt, gross 75,000 Discount on notes payable (1,418 ) Accretion of Paydown Fee 106 Long-term debt $ 73,688

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Summary of supplemental cash flow information related to leases	Supplemental cash flow information related to leases for the period reported is as follows (in thousands, except weighted-average remaining lease term and weighted-average discount rate): Three Months Ended March 31, 2020 2019 ROU assets obtained in exchange for new operating lease upon adoption of ASC 842 $ — $ 14,177 Cash paid for amounts included in the measurement of lease liabilities 1,153 1,117 Weighted-average remaining lease term of operating leases (in years) 10 8.7 Weighted-average discount rate of operating leases 8.7 % 13.2 %
Schedule of Lessee, Operating Lease, Liability, Maturity	As of March 31, 2020, the maturities of our operating lease liabilities were as follows (in thousands): Year ending December 31, Amount 2020 (nine months) $ 5,878 (a) 2021 11,736 2022 12,116 2023 12,508 2024 12,913 2025 13,333 Thereafter 61,035 Total lease payments 129,519 Less: Imputed interest (b) (45,190 ) Present value of operating lease liabilities $ 84,329 (a) Includes our lease payments of $7.1 million, which is partially offset by the expected receipt of the remaining tenant inducements of $1.2 million.

Stock-based Compensation (Table

Stock-based Compensation (Tables)	3 Months Ended
	Mar. 31, 2020
Stock Option Activity	The following summarizes option activity under the 2017 Inducement Plan, 2015 Plan and 2012 Plan: Number of Weighted- Outstanding — December 31, 2019 3,573,860 $ 36.24 Options granted 621,703 66.05 Options exercised (33,937 ) 28.50 Options canceled (27,905 ) 47.16 Outstanding — March 31, 2020 4,133,721 $ 40.72
Valuation Assumptions for Stock Awards	The fair values of stock options granted to employees were calculated using the following assumptions: Three Months Ended March 31, 2020 2019 Expected term (in years) 6.1 6.1 Volatility 69.6%-69.9% 71.6%-72.2% Risk-free interest rate 1.4%-1.8% 2.5%-2.6% Dividend yield — —
Stock-based Compensation Expense Recognized	Total stock-based compensation recognized by function included in the condensed consolidated statements of operations and comprehensive loss was as follows (in thousands): Three Months Ended March 31, 20 20 2019 Research and development $ 5,350 $ 4,023 Selling, general and administrative 11,017 5,430 Total stock-based compensation expense $ 16,367 $ 9,453
Restricted Stock Units [Member]
Non-Vested Restricted Stock Activity	The following table summarizes activity of restricted stock units, or RSUs, granted to employees with service-based vesting under the 2017 Inducement Plan and 2015 Plan and related information: Number of RSUs Weighted- Average Grant Date Fair Value Non-vested 1,848,772 $ 49.19 RSUs granted 1,073,766 66.16 RSUs vested (192,966 ) 45.68 RSUs forfeited (38,413 ) 48.18 Non-vested 2,691,159 $ 56.23

Net Loss per Share (Tables)

Net Loss per Share (Tables)	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Potentially Dilutive Securities that were Not Included in Diluted Net Loss per Share Calculations	The following securities were not included in the diluted net loss per share calculations because their effect was anti-dilutive: Three Months Ended March 31, 2020 2019 Options to purchase common stock 4,133,721 3,813,995 Restricted stock subject to future vesting — 22,856 Restricted stock units 2,691,159 1,626,127 Total 6,824,880 5,462,978

Organization and Basis of Pre_2

Organization and Basis of Presentation - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Cumulative net losses	$ 811,942	$ 738,916

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Assets Measured on Recurring Basis (Detail) - Fair Value Measurements, Recurring [Member] - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value	$ 594,536	$ 644,242
U.S. Government Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value	95,896	140,244
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value	294,863	250,535
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value	299,673	393,707
Level 2 [Member] | U.S. Government Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value	95,896	140,244
Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value	294,863	250,535
Money Market Funds [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value	294,863	250,535
Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value	118,390	152,149
Corporate Debt Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value	118,390	152,149
U.S. Government Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value	79,579	95,032
U.S. Government Agency Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value	79,579	95,032
Certificates of Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value	5,808	6,282
Certificates of Deposits [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value	$ 5,808	$ 6,282

Available-for-Sale Securities -

Available-for-Sale Securities - Summary of Available-for-Sale Securities (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Available for sale securities, Amortized Cost	$ 593,321	$ 643,488
Available for sale securities, Unrealized Gains	1,318	766
Available for sale securities, Unrealized (Losses)	(103)	(12)
Available for sale securities, Estimated Fair Value	594,536	644,242	$ 644,242
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for sale securities, Amortized Cost	118,187	151,773
Available for sale securities, Unrealized Gains	287	384
Available for sale securities, Unrealized (Losses)	(84)	(8)
Available for sale securities, Estimated Fair Value	118,390		152,149
U.S. Government Agency Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for sale securities, Amortized Cost	79,417	94,963
Available for sale securities, Unrealized Gains	181	73
Available for sale securities, Unrealized (Losses)	(19)	(4)
Available for sale securities, Estimated Fair Value	79,579		95,032
Money Market Funds [Member]
Debt Securities, Available-for-sale [Line Items]
Available for sale securities, Amortized Cost	294,863	250,535
Available for sale securities, Estimated Fair Value	294,863		250,535
Certificates of Deposits [Member]
Debt Securities, Available-for-sale [Line Items]
Available for sale securities, Amortized Cost	5,766	6,239
Available for sale securities, Unrealized Gains	42	43
Available for sale securities, Unrealized (Losses)		0
Available for sale securities, Estimated Fair Value	5,808		6,282
U.S. Government Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for sale securities, Amortized Cost	95,088	139,978
Available for sale securities, Unrealized Gains	808	266
Available for sale securities, Unrealized (Losses)		$ 0
Available for sale securities, Estimated Fair Value	$ 95,896		$ 140,244

Available-for-Sale Securities_2

Available-for-Sale Securities - Summary of Classification of Available-for-Sale Securities on Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Cash and cash equivalents	$ 294,863	$ 251,480
Short-term marketable securities	215,295	307,732
Long-term marketable securities	84,378	85,030
Total	$ 594,536	$ 644,242	$ 644,242

Balance Sheet Components - Inve

Balance Sheet Components - Inventories (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Balance Sheet Components [Abstract]
Raw materials	$ 7,141	$ 700
Work-in-process	7,217	525
Finished goods	569	52
Inventories	$ 14,927	$ 1,277

Balance Sheet Components - Prop

Balance Sheet Components - Property and Equipment (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 56,160	$ 43,612
Less: accumulated depreciation and amortization	(18,831)	(16,499)
Property and equipment, net	37,329	27,113
Laboratory Equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	8,472	8,314
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	2,224	2,224
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	13,785	13,785
Construction-in-Progress [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 31,679	$ 19,289

Balance Sheet Components - Accr

Balance Sheet Components - Accrued Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Balance Sheet Components [Abstract]
Accrued research and development costs	$ 9,659	$ 26,480
Accrued manufacturing costs	18,160	9,466
Accrued professional and consulting services	4,262	4,564
Accrued sales deductions	1,998	529
Other	483	319
Total accrued liabilities	$ 34,562	$ 41,358

Balance Sheet Components - Othe

Balance Sheet Components - Other Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Balance Sheet Components [Abstract]
Operating lease liabilities, current	$ 2,691	$ 1,866
Other payable	30	30
Total other liabilities, current	$ 2,721	$ 1,896

Long-term Debt - Additional Inf

Long-term Debt - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Dec. 17, 2019
Long term debt	$ 73,688	$ 73,559
Debt issuance costs paid	85
Unamortized fee	800
Term Loan
Debt additional borrowing capacity	$ 75,000
Debt Instrument, Term	72 months
Debt Instrument, Basis Spread on Variable Rate	7.00%
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	2.00%
Debt Instrument Additional Interest Rate On Debt Default	3.00%
Debt Instrument Periodic Payment Of Interest	Interest on amounts outstanding are payable quarterly in arrears
Debt Instrument Periodic Payment Of Interest Term	39 months
Debt additional paydown fee	2.00%
Debt issuance costs paid	$ 1,100
Other debt issuance cost paid	400
Unamortized issuance costs and debt discounts	1,400
Debt additional paydown fee	$ 1,100
Term Loan | Maximum
Debt prepayment fee	3.00%
Term Loan | Minimum
Debt prepayment fee	1.00%
Secured Debt
Debt maximum borrowing capacity			$ 75,000
Debt additional borrowing capacity			$ 75,000
Long term debt		$ 75,000

Long-term Debt-Schedule of Futu

Long-term Debt-Schedule of Future payments of principal and interest on the Term Loan (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Contractual Obligation, Fiscal Year Maturity Schedule [Abstract]
2020	$ 5,063
2021	6,750
2022	6,750
2023	31,406
2024	29,156
2025	26,906
Total minimum payments	106,031
Less amount representing interest	(29,531)
Less amount representing Paydown Fee	(1,500)
Long-term debt, gross	75,000
Discount on notes payable	(1,418)
Accretion of Paydown Fee	106
Long-term debt	$ 73,688	$ 73,559

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	1 Months Ended		3 Months Ended
	Aug. 31, 2018USD ($)ft²	Mar. 31, 2017USD ($)ft²	Mar. 31, 2020USD ($)	Mar. 31, 2019USD ($)
Commitment And Contingencies [Line Items]
Facility size | ft²	164,150	67,185
Initial term		10 years
Future minimum rental payments under the Lease term	$ 121,500,000
Operating lease term		10 years
Operating lease term, optional extension		10 years
Repayment of tenant inducement allowance	4,100,000
Contingency losses			$ 0
Provisions for loss contingency			$ 0
Lease term			10 years	8 years 8 months 12 days
Operating Lease Cost			$ 3,100,000	$ 1,900,000
variable lease cost			700,000	$ 900,000
Repayemnt of tenant inducement allowance to the landlord		$ 1,700,000
Tenant inducements receivable			1,200,000
Operating lease payments			$ 7,100,000
Maximum [Member]
Commitment And Contingencies [Line Items]
Lease term			10 years
Minimum [Member]
Commitment And Contingencies [Line Items]
Lease term			1 year
Leasehold Improvements [Member]
Commitment And Contingencies [Line Items]
Property palnt and equipment additions			$ 30,400,000
Lease Agreements [Member]
Commitment And Contingencies [Line Items]
leasehold improvements Acquired		$ 11,100,000
Lease Agreements [Member] | Maximum [Member]
Commitment And Contingencies [Line Items]
Tenant inducement	$ 27,900,000

Commitments and Contingencies_2

Commitments and Contingencies - Supplemental cash flow information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Commitment And Contingencies [Line Items]
Cash paid for amounts included in the measurement of lease liabilities	$ 1,153	$ 1,117
Weighted-average remaining lease term of operating leases (in years)	10 years	8 years 8 months 12 days
Weighted-average discount rate of operating leases	8.70%	13.20%
Accounting Standards Update 2016-02 [Member]
Commitment And Contingencies [Line Items]
ROU assets obtained in exchange for new operating lease upon adoption of ASC 842		$ 14,177

Commitments and Contingencies_3

Commitments and Contingencies - Lessee Operating Lease Liability Maturity (Detail) $ in Thousands	Mar. 31, 2020USD ($)
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2020	$ 5,878
2021	11,736
2022	12,116
2023	12,508
2024	12,913
2025	13,333
Thereafter	61,035
Total lease payments	129,519
Less: Imputed interest	(45,190)
Present value of operating lease liabilities	$ 84,329

Stock-based Compensation - Plan

Stock-based Compensation - Plan Summary - Additional Information (Detail)	Mar. 31, 2020shares
2017 Inducement Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance	755,891
2015 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance	4,528,603

Stock-based Compensation - Stoc

Stock-based Compensation - Stock Option Activity (Detail)	3 Months Ended
	Mar. 31, 2020$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Beginning balance, outstanding, Number of Options | shares	3,573,860
Options granted, Number of Options | shares	621,703
Options exercised, Number of Options | shares	(33,937)
Options canceled, Number of Options | shares	(27,905)
Ending balance, outstanding, Number of Options | shares	4,133,721
Weighted- Average Exercise Price
Beginning balance, Outstanding, Weighted-Average Exercise Price | $ / shares	$ 36.24
Options granted, Weighted-Average Exercise Price | $ / shares	66.05
Options exercised, Weighted-Average Exercise Price | $ / shares	28.50
Options canceled, Weighted-Average Exercise Price | $ / shares	47.16
Ending balance, Outstanding, Weighted-Average Exercise Price | $ / shares	$ 40.72

Stock-based Compensation - Valu

Stock-based Compensation - Valuation Assumptions for Stock Options Granted (Detail) - Stock Options [Member]	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years 1 month 6 days	6 years 1 month 6 days
Volatility, minimum	69.60%	71.60%
Volatility, maximum	69.90%	72.20%
Risk-free interest rate, minimum	1.40%	2.50%
Risk-free interest rate, maximum	1.80%	2.60%
Dividend yield

Stock-based Compensation - Summ

Stock-based Compensation - Summary of RSU Activity Granted to Employees with Service-Based Vesting (Detail) - 2017 Inducement Plan and 2015 Plan [Member] - RSU [Member]	3 Months Ended
	Mar. 31, 2020$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning Balance - Non-vested market-condition awards | shares	1,848,772
RSUs granted, Number of RSUs | shares	1,073,766
RSUs vested, Number of RSUs | shares	(192,966)
RSUs forfeited, Number of RSUs | shares	(38,413)
Ending Balance - Non-vested market-condition awards | shares	2,691,159
Beginning Balance - Non-vested units, Weighted-Average Grant Date Fair Value | $ / shares	$ 49.19
RSUs granted, Weighted-Average Grant Date Fair Value | $ / shares	66.16
RSUs vested, Weighted-Average Grant Date Fair Value | $ / shares	45.68
RSUs forfeited, Weighted-Average Grant Date Fair Value | $ / shares	48.18
Ending Balance - Non-vested units, Weighted-Average Grant Date Fair Value | $ / shares	$ 56.23

Net Loss per Share - Potentiall

Net Loss per Share - Potentially Dilutive Securities that were Not Included in Diluted Net Loss per Share Calculations (Detail) - shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from earnings per share	6,824,880	5,462,978
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from earnings per share	4,133,721	3,813,995
Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from earnings per share		22,856
RSU [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from earnings per share	2,691,159	1,626,127

Stock-based Compensation - St_2

Stock-based Compensation - Stock-based Compensation Expense Recognized (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 16,367	$ 9,453
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	5,350	4,023
General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 11,017	$ 5,430