Tricida (TCDAQ) 10-Q 8 May 20 2020 Q1 Quarterly report Financial data

Cover Page

Cover Page - $ / shares	3 Months Ended
	Mar. 31, 2020	May 01, 2020	Dec. 31, 2019	Jul. 02, 2018
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2020
Document Transition Report	false
Entity File Number	001-38558
Entity Registrant Name	TRICIDA, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-3372526
Entity Address, Address Line One	7000 Shoreline Court
Entity Address, Address Line Two	Suite 201
Entity Address, City or Town	South San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94080
City Area Code	415
Local Phone Number	429-7800
Title of 12(b) Security	Common stock, par value $0.001 per share
Trading Symbol	TCDA
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		49,951,982
Common stock, par value (in USD per share)	$ 0.001		$ 0.001	$ 0.001
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001595585
Current Fiscal Year End Date	--12-31

CONDENSED BALANCE SHEETS

CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 10,555	$ 18,574
Short-term investments	273,738	289,424
Prepaid expenses and other current assets	5,496	4,744
Total current assets	289,789	312,742
Long-term investments	19,954	46,980
Property and equipment, net	1,420	2,728
Operating lease right-of-use assets	9,056	9,376
Total assets	320,219	371,826
Current liabilities:
Accounts payable	10,994	5,911
Current operating lease liabilities	1,080	1,072
Accrued expenses and other current liabilities	40,063	32,780
Total current liabilities	52,137	39,763
Term Loan	59,125	58,374
Non-current operating lease liabilities	8,650	8,783
Other long-term liabilities	1,846	1,023
Total liabilities	121,758	107,943
Commitments and contingencies (Note 7)
Stockholders’ equity:
Preferred stock, $0.001 par value; 40,000,000 shares authorized, no shares issued or outstanding as of March 31, 2020 and December 31, 2019	0	0
Common stock, $0.001 par value; 400,000,000 shares authorized as of March 31, 2020 and December 31, 2019; 49,913,232 and 49,763,176 shares issued and outstanding as of March 31, 2020 and December 31, 2019, respectively	50	50
Additional paid-in capital	641,571	632,647
Accumulated other comprehensive income (loss)	(39)	193
Accumulated deficit	(443,121)	(369,007)
Total stockholders’ equity	198,461	263,883
Total liabilities and stockholders’ equity	$ 320,219	$ 371,826
Common stock, par value (in USD per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	400,000,000	400,000,000
Common stock, shares outstanding (in shares)	49,913,232	49,763,176

CONDENSED BALANCE SHEETS (Paren

CONDENSED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Preferred stock, par value (in USD per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	40,000,000	40,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in USD per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	400,000,000	400,000,000
Common stock, shares issued (in shares)	49,913,232	49,913,232
Common stock, shares outstanding (in shares)	49,913,232	49,763,176

CONDENSED STATEMENTS OF OPERATI

CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating expenses:
Research and development	$ 49,381	$ 31,423
General and administrative	23,526	6,352
Total operating expenses	72,907	37,775
Loss from operations	(72,907)	(37,775)
Other income (expense), net	813	1,267
Interest expense	(2,020)	(1,389)
Net loss	(74,114)	(37,897)
Other comprehensive income (loss):
Net unrealized gain (loss) on available-for-sale investments, net of tax	(232)	302
Total comprehensive loss	$ (74,346)	$ (37,595)
Net loss per share, basic and diluted (in USD per share)	$ (1.49)	$ (0.90)
Weighted-average number of shares outstanding, basic and diluted (in shares)	49,841,407	42,268,062

CONDENSED STATEMENTS OF CONVERT

CONDENSED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2018		42,148,247
Beginning balance at Dec. 31, 2018	$ 194,525	$ 42	$ 386,830	$ (153)	$ (192,194)
Total Stockholders’ Equity
Issuance of warrant in connection with Term Loan	284		284
Issuance of common stock under equity incentive plans (in shares)		527,859
Issuance of common stock under equity incentive plans	737	$ 1	736
Stock-based compensation	2,658		2,658
Net unrealized gain (loss) on available-for-sale investments, net of tax	302			302
Net loss	(37,897)				(37,897)
Ending balance (in shares) at Mar. 31, 2019		42,676,106
Ending balance at Mar. 31, 2019	$ 160,609	$ 43	390,508	149	(230,091)
Beginning balance (in shares) at Dec. 31, 2019	49,913,232	49,763,176
Beginning balance at Dec. 31, 2019	$ 263,883	$ 50	632,647	193	(369,007)
Total Stockholders’ Equity
Issuance of common stock under equity incentive plans (in shares)		150,056
Issuance of common stock under equity incentive plans	550	$ 0	550
Stock-based compensation	8,374		8,374
Net unrealized gain (loss) on available-for-sale investments, net of tax	(232)			(232)
Net loss	$ (74,114)				(74,114)
Ending balance (in shares) at Mar. 31, 2020	49,913,232	49,913,232
Ending balance at Mar. 31, 2020	$ 198,461	$ 50	$ 641,571	$ (39)	$ (443,121)

CONDENSED STATEMENTS OF CASH FL

CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating activities:
Net loss	$ (74,114)	$ (37,897)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	230	172
Amortization of operating lease right-of-use assets	320	204
Accretion (amortization) of premiums and discounts on investments	(341)	(756)
Amortization of Term Loan discount and issuance costs	751	488
Stock-based compensation	8,374	2,658
Changes in fair value of compound derivative liability	846	174
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(777)	243
Accounts payable	4,892	(3,390)
Accrued expenses and other liabilities	8,910	14,479
Operating lease liabilities	(125)	(217)
Net cash used in operating activities	(51,034)	(23,842)
Investing activities:
Purchases of investments	(46,045)	(44,769)
Maturities of investments	88,867	54,981
Purchases of property and equipment	(360)	(193)
Net cash provided by investing activities	42,462	10,019
Financing activities:
Payments of equity offering costs	0	(321)
Proceeds from issuance of common stock under equity incentive plans	567	251
Repayment of leasehold improvement loan	(14)	(32)
Proceeds (payments) under Term Loan, net	0	(1,319)
Net cash provided by (used in) financing activities	553	(1,421)
Net increase (decrease) in cash and cash equivalents	(8,019)	(15,244)
Cash and cash equivalents at beginning of period	18,574	37,172
Cash and cash equivalents at end of period	10,555	21,928
Supplemental disclosures
Cash paid for interest	1,211	782
Supplemental disclosures of non-cash investing and financing activities
Deferred offering costs incurred but not paid	0	396
Warrants and compound derivative liability related to Term Loan	0	284
Purchase of property and equipment in accounts payable and accrued expenses	$ 206	$ 0

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	ORGANIZATION AND BASIS OF PRESENTATION Organization —Tricida, Inc., or the Company, was incorporated in the state of Delaware on May 22, 2013 and was granted its certification of qualification in the state of California on August 5, 2013, or inception. The Company is focused on the development and commercialization of its drug candidate, veverimer (also known as TRC101), a non-absorbed, orally-administered polymer designed to treat metabolic acidosis in patients with chronic kidney disease. The Company has sustained operating losses and expects such annual losses to continue over the next several years. The Company’s ultimate success depends on the outcome of its research and development and commercialization activities for veverimer, for which it expects to incur additional losses in the future. Through March 31, 2020, the Company has relied primarily on the proceeds from equity offerings and debt financing to finance its operations. The Company recognizes that it may need to raise additional capital to fully implement its business plan, and if market conditions are favorable or if the Company identifies specific strategic opportunities or needs, intends to do so through the issuance of equity, borrowings, or strategic alliances with partner companies. However, if such financing is not available at adequate levels or on reasonable terms, the Company will need to reevaluate its operating plans and could be required to significantly reduce operating expenses and delay, reduce the scope of or eliminate some of its development programs or its future commercialization efforts, out-license intellectual property rights to its product candidates and sell unsecured assets, or a combination of the above, any of which may have a material adverse effect on its business, results of operations, financial condition and/or its ability to fund its scheduled obligations on a timely basis or at all. Basis of Presentation —The accompanying unaudited condensed financial statements have been prepared in accordance with accounting principles generally accepted in the United States, or U.S. GAAP, for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. The condensed balance sheet as of March 31, 2020, the condensed statements of operations and comprehensive loss for the three months ended March 31, 2020 and 2019, the condensed statements of stockholders' equity for the three months ended March 31, 2020 and 2019 and the condensed statements of cash flows for the three months ended March 31, 2020 and 2019 are unaudited, but include all adjustments, consisting only of normal recurring adjustments, which the Company considers necessary for a fair presentation of the financial position, operating results and cash flows for the periods presented. The condensed balance sheet at December 31, 2019 has been derived from audited financial statements. Although the Company believes that the disclosures in these financial statements are adequate to make the information presented not misleading, certain information and footnote information normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES With the exception of the change for the accounting of credit losses as a result of the adoption of Accounting Standards Update, or ASU, 2016-13, Financial Instruments - Credit Losses (Topic 326) : Measurement of Credit Losses on Financial Instruments, or ASU 2016-13, there have been no new or material changes to the significant accounting policies discussed in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019, that are of significance, or potential significance, to the Company. Credit Losses The Company is exposed to credit losses primarily through its available-for-sale investments. The Company invests excess cash in marketable securities with high credit ratings that are classified in Level 1 and Level 2 of the fair value hierarchy. The Company's investment portfolio at any point in time contains investments in U.S. treasury and U.S. government agency securities, taxable and tax-exempt municipal notes, corporate notes and bonds, commercial paper, non-U.S. government agency securities and money market funds, and are classified as available-for-sale. The Company assesses whether its available-for sale investments are impaired at each reporting period. Unrealized losses or impairments resulting from the fair value of the available-for-sale debt security being below the amortized cost basis are evaluated for identification of credit losses and non-credit related losses. Any credit losses are charged to earnings against the allowance for credit losses of the debt security, limited to the difference between the fair value and the amortized cost basis of the debt security. Any difference between the fair value of the debt security and the amortized cost basis, less the allowance for credit losses, are reported in other comprehensive income (loss). Expected cash inflows due to improvements in credit are recognized through a reversal of the allowance for credit losses subject to the total allowance previously recognized. The Company’s expected loss allowance methodology for the debt securities is developed by reviewing the extent of the unrealized loss, the size, term, geographical location, and industry of the issuer, the issuers’ credit ratings and any changes in those ratings, as well as reviewing current and future economic market conditions and the issuers’ current status and financial condition. The Company considered the current and expected future economic and market conditions surrounding the COVID-19 pandemic and determined that the estimate of credit losses was not significantly impacted. As of March 31, 2020, the Company has not recognized an allowance for expected credit losses related to available-for-sale investments as the Company has not identified any unrealized losses for these investments attributable to credit factors. Recent Accounting Pronouncements Adopted Standards Effective January 1, 2020, the Company adopted ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments , which changed the impairment model for most financial assets and certain other instruments. Company adopted ASU 2016-13 on January 1, 2020, using a modified retrospective transition method, which requires a cumulative-effect adjustment, if any, to the opening balance of retained earnings to be recognized on the date of adoption with prior periods not restated. The adoption of ASU 2016-13 did not have a significant impact on the Company's condensed financial statements. See "Credit Losses" above for a description of the Company's credit losses accounting policy. Standards Not Yet Effective

FAIR VALUE MEASUREMENTS AND FAI

FAIR VALUE MEASUREMENTS AND FAIR VALUE OF FINANCIAL INSTRUMENTS	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS AND FAIR VALUE OF FINANCIAL INSTRUMENTS	FAIR VALUE MEASUREMENTS AND FAIR VALUE OF FINANCIAL INSTRUMENTS The fair value of the Company’s financial assets and liabilities are determined in accordance with the fair value hierarchy established in the FASB's ASC Topic 820, Fair Value Measurements and Disclosures, or Topic 820. ASC Topic 820 defines fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The fair value hierarchy of Topic 820 requires an entity to maximize the use of observable inputs when measuring fair value and classifies those inputs into three levels: Level 1 —Observable inputs, such as quoted prices in active markets; Level 2 —Inputs, other than the quoted prices in active markets, which are observable either directly or indirectly such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the instrument’s anticipated life; and Level 3 —Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. Our financial instruments consist primarily of cash and cash equivalents, short-term and long-term investments, accounts payable and the Loan and Security Agreement, or Term Loan, entered into with Hercules Capital Inc., or Hercules. Cash, cash equivalents and investments are reported at their respective fair values on the Company's condensed balance sheets. Where quoted prices are available in an active market, securities are classified as Level 1. The Company classifies money market funds as Level 1. When quoted market prices are not available for the specific security, then the Company estimates fair value by using quoted prices for identical or similar instruments in markets that are not active and model-based valuation techniques for which all significant inputs are observable in the market or can be corroborated by observable market data for substantially the full term of the assets. Where applicable, these models project future cash flows and discount the future amounts to a present value using market-based observable inputs obtained from various third-party data providers, including but not limited to benchmark yields, reported trades and broker/dealer quotes. Where applicable the market approach utilizes prices and information from market transactions for similar or identical assets. The Company classifies U.S. government agency securities, commercial paper, corporate debt securities and asset-backed securities as Level 2. The Company's short-term and long-term investments are classified as available-for-sale. The following tables set forth the value of the Company's financial assets remeasured on a recurring basis based on the three-tier fair value hierarchy by significant investment category as of March 31, 2020 and December 31, 2019. March 31, 2020 Reported as: (in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Cash and Cash Equivalents Short-Term Investments Long-Term Investments Cash $ 2,257 $ — $ — $ 2,257 $ 2,257 $ — $ — Level 1: Money market fund 8,298 — — 8,298 8,298 — — Level 2: U.S. government agency securities 24,247 13 — 24,260 — 21,505 2,755 Commercial paper 83,255 300 — 83,555 — 83,555 — Corporate debt securities 186,137 123 (383) 185,877 — 168,678 17,199 Subtotal 293,639 436 (383) 293,692 — 273,738 19,954 Total assets measured at fair value $ 304,194 $ 436 $ (383) $ 304,247 $ 10,555 $ 273,738 $ 19,954 December 31, 2019 Reported as: (in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Cash and Cash Equivalents Short-Term Investments Long-Term Investments Cash $ 1,393 $ — $ — $ 1,393 $ 1,393 $ — $ — Level 1: Money market fund 17,181 — — 17,181 17,181 — — Level 2: U.S. government agency securities 40,741 6 (14) 40,733 — 19,990 20,743 Commercial paper 108,248 107 (2) 108,353 — 108,353 — Corporate debt securities 185,569 205 (20) 185,754 — 159,517 26,237 Asset-backed securities 1,561 3 — 1,564 — 1,564 — Subtotal 336,119 321 (36) 336,404 — 289,424 46,980 Total assets measured at fair value $ 354,693 $ 321 $ (36) $ 354,978 $ 18,574 $ 289,424 $ 46,980 Interest income related to the Company's cash, cash equivalents and available-for-sale investments included in other income (expense), net was approximately $1.7 million and $1.6 million for the three months ended March 31, 2020 and 2019, respectively. There were no gross realized gains and gross realized losses for the three months ended March 31, 2020 and 2019. The following table summarizes the Company's available-for-sale investments that were in a continuous unrealized loss position but not deemed credit losses and therefore not required to be charged to earnings against the allowance for expected credit losses, as of March 31, 2020 and December 31, 2019. March 31, 2020 December 31, 2019 (in thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses U.S. government agency securities $ — $ — $ 24,235 $ (14) Commercial paper — — 5,426 (2) Corporate debt securities 103,083 (383) 38,668 (20) Total $ 103,083 $ (383) $ 68,329 $ (36) The Company held a total of 33 and 18 positions which were in an unrealized loss position as of March 31, 2020 and December 31, 2019, respectively. All available-for-sale investments in an unrealized loss position were in a continuous loss position for less than 12 months. The Company determined that there was no allowance for expected credit losses related to our available-for-sale investments as of March 31, 2020 because the Company does not intend to sell these securities nor does the Company believe that it will be required to sell these securities before the recovery of their amortized cost basis. The following table summarizes the maturities of the Company’s cash equivalents (excluding money market funds) and available-for-sale investments, as of March 31, 2020. (in thousands) Amortized Cost Fair Value Mature in less than one year $ 273,656 $ 273,738 Mature in one to five years 19,983 19,954 Total $ 293,639 $ 293,692 The following table presents a reconciliation of financial liabilities related to the compound derivative liability associated with the Term Loan measured at fair value on a recurring basis using Level 3 unobservable inputs for the three months ended March 31, 2020 and 2019. Three Months Ended March 31, 2020 2019 (in thousands) Compound Derivative Liability Compound Derivative Liability Fair value at beginning of period $ 977 $ 161 Change in fair value 846 174 Fair value at end of period $ 1,823 $ 335 The following table presents information about significant unobservable inputs related to the Company's Level 3 financial liabilities as of March 31, 2020. March 31, 2020 (in thousands) Fair Value Valuation Technique Significant Unobservable Input Input Compound derivative liability $ 1,823 Discounted cash flow Discount rate 16.8 % Probability of the occurrence of certain events 20.0 % Term Loan The estimated fair value of the Term Loan was $52.7 million as of March 31, 2020 and is classified as Level 3. The key valuation assumptions used consist of the discount rate of 16.8% and the probability of the occurrence of certain events of 20.0%.

LEASES

LEASES	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
LEASES	LEASES The Company accounts for leases under ASU No. 2016-02, Leases (Topic 842) , adopted as of January 1, 2019. In July 2014, the Company entered into a five On August 14, 2019, the Company entered into a third amendment to the existing operating lease which will extend the leased space by an additional 19,177 square feet, or Second Expansion Premises, which will result in a total of 46,074 square feet being leased in aggregate. The operating lease for the Second Expansion Premises will commence on the date they are delivered to the Company, which is expected to be September 1, 2020, or the Second Expansion Premises Commencement Date. In conjunction with the third amendment, the Company also agreed to lease 5,569 square feet of temporary office space effective August 15, 2019 to the Second Expansion Premises Commencement Date. The third amendment will extend the lease by 84 months from the Second Expansion Premises Commencement Date, with an option to extend the lease for an additional 36 months subject to certain conditions. The Company determined that the Second Expansion Premises shall be accounted for as a new lease at the Second Expansion Premises Commencement Date. Further, the Company determined that the amendment to the existing operating lease and temporary office space shall be accounted as a lease modification upon execution of the third amendment. The Company recognized an operating lease ROU asset of $8.1 million and operating lease liability of $8.1 million on its condensed balance sheet upon the execution of the third amendment on August 14, 2019, and will measure and record an additional ROU asset and operating lease liability for the Second Expansion Premises upon the Second Expansion Premises Commencement Date. Operating lease cost was $0.5 million and $0.3 million for the three months ended March 31, 2020 and 2019, respectively. Variable lease cost was $0.2 million and $0.2 million for the three months ended March 31, 2020 and 2019, respectively. Operating cash flows for the three months ended March 31, 2020 and 2019 included $0.3 million and $0.3 million, respectively in cash payments for operating leases. Expense related to short-term leases was not significant for the three months ended March 31, 2020 and 2019. The following table presents the maturity analysis of the Company's operating lease liabilities showing the aggregate lease payments as of March 31, 2020. (in thousands) March 31, 2020 (remaining nine months) $ 835 2021 1,377 2022 1,662 2023 1,712 2024 1,763 2025 and thereafter 4,959 Total lease payments (1) 12,308 Less: imputed interest (2,578) Total operating lease liabilities $ 9,730 (1) As noted above, the operating lease for the Second Expansion Premises is expected to commence on September 1, 2020 and therefore the lease related to the Second Expansion Premises is not recognized on the condensed consolidated balance sheet as of March 31, 2020. As of March 31, 2020, future minimum lease payments related to the Second Expansion Premises are expected to be $8.2 million over the lease term of 7.0 years. Operating lease liabilities are based on the net present value of the remaining lease payments over the remaining lease term. In determining the present value of lease payments, the Company uses its incremental borrowing rate. The weighted-average incremental borrowing rate used to determine the operating lease liabilities was 6.0% and 8.0% as of March 31, 2020 and 2019, respectively. The Company's weighted-average remaining lease term was 7.4 years and 2.3 years as of March 31, 2020 and 2019, respectively.

OTHER BALANCE SHEET COMPONENTS

OTHER BALANCE SHEET COMPONENTS	3 Months Ended
	Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
OTHER BALANCE SHEET COMPONENTS	OTHER BALANCE SHEET COMPONENTSProperty and Equipment, Net The following table presents the components of property and equipment, net as of March 31, 2020 and December 31, 2019. (in thousands) March 31, December 31, Furniture and fixtures $ 274 $ 265 Computer and lab equipment 2,780 3,867 Leasehold improvements 1,244 1,244 4,298 5,376 Less: accumulated depreciation and amortization (2,878) (2,648) Total property and equipment, net $ 1,420 $ 2,728 Depreciation and amortization expense was approximately $0.2 million for the three months ended March 31, 2020 and 2019. Accrued Expenses and Other Current Liabilities The following table presents the components of accrued expenses and other current liabilities as of March 31, 2020 and December 31, 2019. (in thousands) March 31, December 31, Accrued clinical and nonclinical study costs $ 11,599 $ 8,343 Accrued contract manufacturing 18,287 17,343 Accrued compensation 3,583 3,367 Accrued professional fees and other 6,594 3,727 Total accrued expenses and other current liabilities $ 40,063 $ 32,780

BORROWINGS

BORROWINGS	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
BORROWINGS	BORROWINGS Term Loan On February 28, 2018, the Company entered into the Term Loan with Hercules. The Term Loan provided for a loan in an aggregate principal amount of up to $100.0 million to be funded in five tranches subject to certain performance-based milestones. The first tranche, in the amount of $25.0 million, was funded on the closing date of the Term Loan. On October 15, 2018, the Company and Hercules entered into the second amendment to the Term Loan, which amended certain terms of the Term Loan. After giving effect to the second amendment, the Term Loan continued to provide for a loan in an aggregate principal amount of up to $100.0 million to be funded in five tranches subject to certain performance-based milestones. The second tranche was reduced from $25.0 million to $15.0 million and was funded on December 28, 2018. The Company accounted for the second amendment as a modification to the existing Term Loan. On March 27, 2019, the Company modified the Term Loan with Hercules by entering into the third amendment to the Term Loan. After giving effect to the third amendment, the amount available under the Term Loan was increased from up to $100.0 million to up to $200.0 million to be funded in tranches, subject to certain performance-based milestones, and the maturity of the Term Loan was extended. Under the terms of the Term Loan, as amended by the third amendment, the $40.0 million of principal outstanding under the Term Loan at the date of modification remains outstanding, and additional tranches of $20.0 million and $15.0 million available for draw down prior to December 15, 2019 and December 15, 2020, respectively. An additional tranche of $75.0 million will be available for draw down between January 1, 2020 and December 15, 2020, on the condition that the Company obtains final approval from the U.S. Food and Drug Administration, or FDA, for the New Drug Application, or NDA for veverimer. A final tranche of $50.0 million will be available for draw down on or prior to December 15, 2021, upon request by the Company and the approval of Hercules' investment committee. The Company accounted for the third amendment as a modification to the existing Term Loan. On December 13, 2019, the third tranche of the Term Loan was funded in the amount of $20.0 million. On March 31, 2020, the Company and Hercules entered into the fourth amendment to the Term Loan. After giving effect to the fourth amendment, the fourth tranche of amount $15.0 million previously under Hercules Capital, Inc. was split between two lenders, $5.0 million under Hercules Capital, Inc. and $10.0 million under Hercules Technology III, L.P. The Company accounted for the fourth amendment as a modification to the existing Term Loan. The Term Loan bears interest at a floating per annum interest rate equal to the greater of either (i) 8.35% or (ii) the lesser of (x) 8.35% plus the prime rate as reported in The Wall Street Journal minus 6.00% and (y) 9.85%. The maturity date is extended to April 1, 2023 and may be extended to April 1, 2024 if the tranche of $75.0 million described above is drawn. The Company will initially be making interest-only payments until April 1, 2021. If the Company achieves certain performance milestones and financial covenants, the interest-only period could be extended for up to an additional 24 months. Upon expiration of the interest-only period, the Company will repay the Term Loan in equal monthly installments comprised of principal and interest, based on a 30-month amortization schedule, through maturity. The Company will pay an additional amount of (a) $2.6 million due on March 1, 2022 and (b) the product of 7.55% and the aggregate loans funded under the Term Loan due at maturity or on any earlier date on which the loans become due. If the Company prepays the Term Loan, the Company will be required to pay a prepayment charge equal to (i) 2.00% of the amount being prepaid at any time during the first 12 months following the effective date of the third amendment (ii) 1.50% of the amount being prepaid after 12 months but prior to 24 months following the effective date of the third amendment (iii) 1.00% of the amount being prepaid after 24 months but prior to 36 months following the effective date of the third amendment and (iv) zero if prepaid any time after 36 months following the effective date of the third amendment but prior to the maturity. The Term Loan is secured by substantially all of the Company's assets, except its intellectual property, which is the subject of a negative pledge; however, the collateral does consist of rights to payments and proceeds from the sale, licensing or disposition of all or any part of, or rights in, its intellectual property. Under the Term Loan, the Company is subject to certain covenants, including but not limited to requirements to deliver financial reports at designated times of the year and maintain a minimum level of cash. These covenants also limit or restrict the Company's ability to incur additional indebtedness or liens, acquire, own or make any investments, pay cash dividends, repurchase stock or enter into certain corporate transactions, including mergers and changes of control. Warrants In conjunction with the Term Loan entered into on February 28, 2018, the Company issued a warrant to Hercules to purchase 53,458 shares of its common stock with an exercise price of $9.35 per share. The estimated fair value of the warrant at the date of issuance was approximately $0.2 million. The fair value of the common stock warrant liability was determined using the probability-weighted expected return method. It was recorded at its fair value at inception and was remeasured at each financial reporting period with any changes in fair value being recognized as a component of other income (expense), net in the accompanying condensed statements of operations and comprehensive loss. On April 10, 2018, the Company entered into amendments with Hercules that resulted in the reclassification of the warrant liability to stockholders' equity as the amended terms of the warrants qualified for them to be accounted for as equity instruments and, as such, were no longer subject to remeasurement. The fair value of the common stock warrants of approximately $0.2 million was reclassified to stockholders' equity upon execution of the amendment. In connection with the funding of the second tranche on December 28, 2018, the Company issued to Hercules a warrant to purchase 53,458 shares of its common stock at an exercise price of $9.35 per share. The common stock warrant was recorded in stockholders' equity at its fair value of approximately $0.9 million on December 28, 2018. In conjunction with the third amendment, the Company issued warrants to Hercules to purchase 16,721 shares of its common stock with an exercise price of $23.92 per share. The common stock warrants were recorded in stockholders' equity at their fair value of approximately $0.3 million on March 27, 2019. The fair value of the common stock warrants were determined using an option-pricing model with the following assumptions: time to liquidity of 7.0 years, volatility of 75.0%, risk-free rate of 2.3% and stock price based on the March 27, 2019 closing price of the Company's common stock reported by The Nasdaq Global Select Market. In connection with the funding of the third tranche on December 13, 2019, or the issuance date, the Company issued to Hercules a warrant to purchase 8,361 shares of its common stock at an exercise price of $23.92 per share. The common stock warrant was recorded in stockholders' equity at its fair value of approximately $0.3 million on the issuance date. The fair value of the common stock warrants was determined using an option-pricing model with the following assumptions: time to liquidity of 7.0 years, volatility of 72.7%, risk-free rate of 1.8% and stock price based on the December 13, 2019 closing price of the Company's common stock reported by The Nasdaq Global Select Market. In connection with each subsequent draw down under the tranches described above, the Company is obligated to issue additional warrants to purchase a number of shares of the Company's common stock determined by dividing (x) an amount equal to 1.0% of the principal amount of the applicable tranche by (y) $23.92 subject to adjustments following certain corporate events. Embedded Derivatives and Other Debt Issuance Costs The Company determined that certain loan features were embedded derivatives requiring bifurcation and separate accounting. Those embedded derivatives were bundled together as a single, compound embedded derivative and then bifurcated and accounted for separately from the host contract. The Company initially recorded a compound derivative liability of $0.7 million, which is required to be marked to market in future periods. As of March 31, 2020, the Company calculated the fair values of the compound derivative using the “with and without” method under the income approach by computing the difference between the fair value of the Term Loan with the compound derivative, and the fair value of the Term Loan without the compound derivative. The Company calculated the fair values using a probability-weighted discounted cash flow analysis. The key valuation assumptions used consist of the discount rate of 16.8% and the probability of the occurrence of certain events of 20.0%. The compound derivative liability is being remeasured at each financial reporting period with any changes in fair value being recognized as a component of other income (expense), net in the condensed statements of operations and comprehensive loss. The fair value of the compound derivative liability was approximately $1.8 million as of March 31, 2020 and was classified as other long-term liabilities on the condensed balance sheet. The facility fee, fair value of warrants at issuance, fair value of embedded derivatives which were bifurcated, and other debt issuance costs have been treated as debt discounts on the Company’s condensed balance sheet and together with the additional payment are being amortized to interest expense throughout the life of the Term Loan using the effective interest rate method. As of March 31, 2020 and December 31, 2019, there were unamortized issuance costs and debt discounts of $3.3 million and $3.6 million, respectively, which were recorded as a direct deduction from the Term Loan on the condensed balance sheets. The following table presents future payments of principal and interest on the Term Loan as of March 31, 2020. (in thousands) March 31, 2020 (remaining nine months) $ 3,828 2021 21,259 2022 26,675 2023 19,893 71,655 Less: amount representing interest (11,655) Present value of Term Loan 60,000 Less: current portion — Long-term portion of Term Loan $ 60,000

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES The Company has contractual obligations from its operating lease, manufacturing and service contracts, Term Loan and tenant improvement loan, and other research and development activities. The following table aggregates the Company’s material expected contractual obligations and commitments as of March 31, 2020. March 31, 2020 (in thousands) Total 2020 (4) 2021 - 2022 2023 - 2024 Thereafter Term Loan (1) $ 71,655 $ 3,828 $ 47,934 $ 19,893 $ — Lease obligations (2) 20,502 1,037 5,018 5,953 8,494 Tenant improvement loan 117 70 47 — — Manufacturing and service contracts (3) 587,046 51,131 83,107 113,202 339,606 Total contractual obligations and commitments $ 679,320 $ 56,066 $ 136,106 $ 139,048 $ 348,100 (1) The long-term debt obligation is comprised of the fourth amendment to the Term Loan that was executed in March 2020. (2) These amounts are comprised of the rent payments on our existing lease and on the Second Expansion Premises which will commence on September 2020 under our amended lease that was executed on August 14, 2019. (3) The purchase obligations are comprised of our non-cancelable purchase commitments under our Manufacturing and Commercial Supply Agreement with Patheon. These amounts are based on forecasts that may include estimates of our future market demand, quantity discounts and manufacturing efficiencies. (4) Remaining nine months. Facilities The Company has an operating lease for its offices and laboratory space in South San Francisco. See Note 4. "Leases" for additional information about this lease. Other Commitments On October 4, 2019, the Company and Patheon Austria GmbH & Co KG, or Patheon, entered into a multi-year Manufacturing and Commercial Supply Agreement, or the Supply Agreement, under which Patheon agreed to manufacture and supply veverimer to support the Company's commercialization efforts. Patheon has also agreed to manufacture and supply veverimer to support the Company’s drug development and clinical trial activities. Under the Supply Agreement, the Company is obligated to make certain purchases of API. The Company and Patheon are also parties to a Master Development/Validation Services and Clinical/Launch Supply Agreement, or the MDA, pursuant to which Patheon agreed to manufacture and supply veverimer. Certain manufacturing activities previously governed by the MDA are now subject to the Supply Agreement, whereas other ongoing manufacturing activities under the MDA will continue to be governed by the MDA until such activities are complete. The Supply Agreement may be terminated by either party following an uncured material breach by the other party, in the event the other party becomes insolvent or subject to bankruptcy proceedings, or in connection with a force majeure event that continues beyond 12 months. In addition, the Supply Agreement may be terminated by the Company upon the occurrence of certain regulatory events or actions, including: (i) if the Company does not obtain regulatory approval for veverimer by a specified date or (ii) if the Company terminates its commercialization of veverimer or fails to launch veverimer by a specified date. The Company’s obligation to purchase veverimer is subject to minimum and maximum annual commitments, with the minimum commitments subject to reduction in certain circumstances. Patheon has agreed to make facility improvements under the Supply Agreement and will be the exclusive owner of the purchased equipment and facility improvements. Patheon may manufacture other products with the facility improvements when not occupied by manufacturing veverimer. Under the Supply Agreement, the Company has agreed to reimburse Patheon up to a specified amount for plant modifications. These payments will be expensed to research and development prior to FDA approval of veverimer. The Company also enters into other contracts in the normal course of business with contract research organizations, contract development and manufacturing organizations and other service providers and vendors. These contracts generally provide for termination on short notice and are cancelable contracts and accordingly, are not included in the contractual obligations and disclosures summarized above. Contingencies While there are no legal proceedings the Company is aware of, the Company may become party to various claims and complaints arising in the ordinary course of business. The Company does not believe that any ultimate liability resulting from any of these claims will have a material adverse effect on its results of operations, financial position, or liquidity. However, the Company cannot give any assurance regarding the ultimate outcome of these claims, and their resolution could be material to operating results for any particular period, depending upon the level of income for the period. Guarantees and Indemnifications The Company indemnifies each of its directors and officers for certain events or occurrences, subject to certain limits, while the director is or was serving at the Company’s request in such capacity, as permitted under Delaware law and in accordance with its certificate of incorporation and bylaws. The term of the indemnification period lasts as long as a director may be subject to any proceeding arising out of acts or omissions of such director in such capacity. The maximum amount of potential future indemnification is unlimited; however, the Company currently holds director and officer liability insurance. This insurance allows the transfer of risk associated with the Company’s exposure and may enable it to recover a portion of any future amounts paid. The Company believes that the fair value of these indemnification obligations is minimal. Accordingly, it has not recognized any liabilities relating to these obligations for any period presented.

STOCKHOLDERS' EQUITY

STOCKHOLDERS' EQUITY	3 Months Ended
	Mar. 31, 2020
Equity [Abstract]
STOCKHOLDERS' EQUITY	STOCKHOLDERS' EQUITY On July 2, 2018, the Company’s amended and restated certificate of incorporation became effective, authorizing the Company to issue a total of 440,000,000 shares of all classes of capital stock, consisting of 400,000,000 shares of common stock, par value $0.001 per share, and 40,000,000 shares of preferred stock, par value $0.001 per share. As of March 31, 2020 and December 31, 2019, the Company had 49,913,232 and 49,763,176 shares of common stock outstanding, respectively. As of March 31, 2020, and December 31, 2019, the Company had no shares of preferred stock outstanding. Common Stock On April 8, 2019, the Company consummated an underwritten public offering and issued 6,440,000 shares of common stock, which included the exercise in full by the underwriters of their option to purchase 840,000 additional shares of common stock at an offering price of $36.00 per share for net proceeds of approximately $217.9 million, after deducting underwriting discounts and commissions of $13.9 million. Common stock reserved for future issuance as of March 31, 2020 and December 31, 2019, consisted of the following. March 31, December 31, Stock options and RSUs issued and outstanding 9,009,511 6,809,257 Stock options, RSUs and ESPP shares authorized for future issuance 3,395,164 3,257,316 Total 12,404,675 10,066,573

NET LOSS PER SHARE

NET LOSS PER SHARE	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
NET LOSS PER SHARE	NET LOSS PER SHARE The following table sets forth the computation of the basic and diluted net loss per share attributable to common stockholders for the three months ended March 31, 2020 and 2019. Three Months Ended (In thousands, except share and per share amounts) 2020 2019 Numerator: Net loss $ (74,114) $ (37,897) Denominator: Weighted-average common shares outstanding 49,845,621 42,283,526 Less: weighted-average shares subject to repurchase (4,214) (15,464) Weighted-average number of shares used in basic and diluted net loss per share 49,841,407 42,268,062 Net loss per share, basic and diluted $ (1.49) $ (0.90) Since the Company was in a loss position for all periods presented, basic net loss per share is the same as diluted net loss per share for all periods as the inclusion of all potential common shares outstanding would have been anti-dilutive. The following weighted-average outstanding common stock equivalents were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been antidilutive. March 31, 2020 2019 Warrants to purchase common stock 131,998 123,637 Common stock subject to repurchase 3,780 12,621 Options and RSUs issued and outstanding 9,009,511 5,798,844 Total potential common shares excluded from the computation of diluted net loss per share 9,145,289 5,935,102

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 Presentation —The accompanying unaudited condensed financial statements have been prepared in accordance with accounting principles generally accepted in the United States, or U.S. GAAP, for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. The condensed balance sheet as of March 31, 2020, the condensed statements of operations and comprehensive loss for the three months ended March 31, 2020 and 2019, the condensed statements of stockholders' equity for the three months ended March 31, 2020 and 2019 and the condensed statements of cash flows for the three months ended March 31, 2020 and 2019 are unaudited, but include all adjustments, consisting only of normal recurring adjustments, which the Company considers necessary for a fair presentation of the financial position, operating results and cash flows for the periods presented. The condensed balance sheet at December 31, 2019 has been derived from audited financial statements.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Adopted Standards Effective January 1, 2020, the Company adopted ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments , which changed the impairment model for most financial assets and certain other instruments. Company adopted ASU 2016-13 on January 1, 2020, using a modified retrospective transition method, which requires a cumulative-effect adjustment, if any, to the opening balance of retained earnings to be recognized on the date of adoption with prior periods not restated. The adoption of ASU 2016-13 did not have a significant impact on the Company's condensed financial statements. See "Credit Losses" above for a description of the Company's credit losses accounting policy. Standards Not Yet Effective

FAIR VALUE MEASUREMENTS AND F_2

FAIR VALUE MEASUREMENTS AND FAIR VALUE OF FINANCIALINSTRUMENTS (Tables)	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Cash and financial assets remeasured on a recurring basis by hierarchy	The following tables set forth the value of the Company's financial assets remeasured on a recurring basis based on the three-tier fair value hierarchy by significant investment category as of March 31, 2020 and December 31, 2019. March 31, 2020 Reported as: (in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Cash and Cash Equivalents Short-Term Investments Long-Term Investments Cash $ 2,257 $ — $ — $ 2,257 $ 2,257 $ — $ — Level 1: Money market fund 8,298 — — 8,298 8,298 — — Level 2: U.S. government agency securities 24,247 13 — 24,260 — 21,505 2,755 Commercial paper 83,255 300 — 83,555 — 83,555 — Corporate debt securities 186,137 123 (383) 185,877 — 168,678 17,199 Subtotal 293,639 436 (383) 293,692 — 273,738 19,954 Total assets measured at fair value $ 304,194 $ 436 $ (383) $ 304,247 $ 10,555 $ 273,738 $ 19,954 December 31, 2019 Reported as: (in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Cash and Cash Equivalents Short-Term Investments Long-Term Investments Cash $ 1,393 $ — $ — $ 1,393 $ 1,393 $ — $ — Level 1: Money market fund 17,181 — — 17,181 17,181 — — Level 2: U.S. government agency securities 40,741 6 (14) 40,733 — 19,990 20,743 Commercial paper 108,248 107 (2) 108,353 — 108,353 — Corporate debt securities 185,569 205 (20) 185,754 — 159,517 26,237 Asset-backed securities 1,561 3 — 1,564 — 1,564 — Subtotal 336,119 321 (36) 336,404 — 289,424 46,980 Total assets measured at fair value $ 354,693 $ 321 $ (36) $ 354,978 $ 18,574 $ 289,424 $ 46,980
Available-for-sale investment in a continuous unrealized loss position but not deemed OTTI	The following table summarizes the Company's available-for-sale investments that were in a continuous unrealized loss position but not deemed credit losses and therefore not required to be charged to earnings against the allowance for expected credit losses, as of March 31, 2020 and December 31, 2019. March 31, 2020 December 31, 2019 (in thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses U.S. government agency securities $ — $ — $ 24,235 $ (14) Commercial paper — — 5,426 (2) Corporate debt securities 103,083 (383) 38,668 (20) Total $ 103,083 $ (383) $ 68,329 $ (36)
Maturities of cash equivalents and available-for-sale investments	The following table summarizes the maturities of the Company’s cash equivalents (excluding money market funds) and available-for-sale investments, as of March 31, 2020. (in thousands) Amortized Cost Fair Value Mature in less than one year $ 273,656 $ 273,738 Mature in one to five years 19,983 19,954 Total $ 293,639 $ 293,692
Reconciliation of liabilities using Level 3 unobservable inputs	The following table presents a reconciliation of financial liabilities related to the compound derivative liability associated with the Term Loan measured at fair value on a recurring basis using Level 3 unobservable inputs for the three months ended March 31, 2020 and 2019. Three Months Ended March 31, 2020 2019 (in thousands) Compound Derivative Liability Compound Derivative Liability Fair value at beginning of period $ 977 $ 161 Change in fair value 846 174 Fair value at end of period $ 1,823 $ 335
Significant fair value unobservable inputs	The following table presents information about significant unobservable inputs related to the Company's Level 3 financial liabilities as of March 31, 2020. March 31, 2020 (in thousands) Fair Value Valuation Technique Significant Unobservable Input Input Compound derivative liability $ 1,823 Discounted cash flow Discount rate 16.8 % Probability of the occurrence of certain events 20.0 %

LEASES (Tables)

LEASES (Tables)	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Operating lease maturity schedule	The following table presents the maturity analysis of the Company's operating lease liabilities showing the aggregate lease payments as of March 31, 2020. (in thousands) March 31, 2020 (remaining nine months) $ 835 2021 1,377 2022 1,662 2023 1,712 2024 1,763 2025 and thereafter 4,959 Total lease payments (1) 12,308 Less: imputed interest (2,578) Total operating lease liabilities $ 9,730 (1) As noted above, the operating lease for the Second Expansion Premises is expected to commence on September 1, 2020 and therefore the lease related to the Second Expansion Premises is not recognized on the condensed consolidated balance sheet as of March 31, 2020. As of March 31, 2020, future minimum lease payments related to the Second Expansion Premises are expected to be $8.2 million over the lease term of 7.0 years.

OTHER BALANCE SHEET COMPONENTS

OTHER BALANCE SHEET COMPONENTS (Tables)	3 Months Ended
	Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Property and Equipment, Net	The following table presents the components of property and equipment, net as of March 31, 2020 and December 31, 2019. (in thousands) March 31, December 31, Furniture and fixtures $ 274 $ 265 Computer and lab equipment 2,780 3,867 Leasehold improvements 1,244 1,244 4,298 5,376 Less: accumulated depreciation and amortization (2,878) (2,648) Total property and equipment, net $ 1,420 $ 2,728
Schedule of Accrued Expenses and Other Current Liabilities	The following table presents the components of accrued expenses and other current liabilities as of March 31, 2020 and December 31, 2019. (in thousands) March 31, December 31, Accrued clinical and nonclinical study costs $ 11,599 $ 8,343 Accrued contract manufacturing 18,287 17,343 Accrued compensation 3,583 3,367 Accrued professional fees and other 6,594 3,727 Total accrued expenses and other current liabilities $ 40,063 $ 32,780

BORROWINGS (Tables)

BORROWINGS (Tables)	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Schedule of Future Payments of Principal and Interest	The following table presents future payments of principal and interest on the Term Loan as of March 31, 2020. (in thousands) March 31, 2020 (remaining nine months) $ 3,828 2021 21,259 2022 26,675 2023 19,893 71,655 Less: amount representing interest (11,655) Present value of Term Loan 60,000 Less: current portion — Long-term portion of Term Loan $ 60,000

Commitment and Contingencies (T

Commitment and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Contractual Obligation, Fiscal Year Maturity	The following table aggregates the Company’s material expected contractual obligations and commitments as of March 31, 2020. March 31, 2020 (in thousands) Total 2020 (4) 2021 - 2022 2023 - 2024 Thereafter Term Loan (1) $ 71,655 $ 3,828 $ 47,934 $ 19,893 $ — Lease obligations (2) 20,502 1,037 5,018 5,953 8,494 Tenant improvement loan 117 70 47 — — Manufacturing and service contracts (3) 587,046 51,131 83,107 113,202 339,606 Total contractual obligations and commitments $ 679,320 $ 56,066 $ 136,106 $ 139,048 $ 348,100 (1) The long-term debt obligation is comprised of the fourth amendment to the Term Loan that was executed in March 2020. (2) These amounts are comprised of the rent payments on our existing lease and on the Second Expansion Premises which will commence on September 2020 under our amended lease that was executed on August 14, 2019. (3) The purchase obligations are comprised of our non-cancelable purchase commitments under our Manufacturing and Commercial Supply Agreement with Patheon. These amounts are based on forecasts that may include estimates of our future market demand, quantity discounts and manufacturing efficiencies. (4) Remaining nine months.

STOCKHOLDERS' EQUITY (Tables)

STOCKHOLDERS' EQUITY (Tables)	3 Months Ended
	Mar. 31, 2020
Equity [Abstract]
Schedule of Common Stock Reserved for Future Issuance	Common stock reserved for future issuance as of March 31, 2020 and December 31, 2019, consisted of the following. March 31, December 31, Stock options and RSUs issued and outstanding 9,009,511 6,809,257 Stock options, RSUs and ESPP shares authorized for future issuance 3,395,164 3,257,316 Total 12,404,675 10,066,573

NET LOSS PER SHARE (Tables)

NET LOSS PER SHARE (Tables)	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Basic and diluted net loss per share	The following table sets forth the computation of the basic and diluted net loss per share attributable to common stockholders for the three months ended March 31, 2020 and 2019. Three Months Ended (In thousands, except share and per share amounts) 2020 2019 Numerator: Net loss $ (74,114) $ (37,897) Denominator: Weighted-average common shares outstanding 49,845,621 42,283,526 Less: weighted-average shares subject to repurchase (4,214) (15,464) Weighted-average number of shares used in basic and diluted net loss per share 49,841,407 42,268,062 Net loss per share, basic and diluted $ (1.49) $ (0.90)
Antidilutive securities excluded from computation	The following weighted-average outstanding common stock equivalents were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been antidilutive. March 31, 2020 2019 Warrants to purchase common stock 131,998 123,637 Common stock subject to repurchase 3,780 12,621 Options and RSUs issued and outstanding 9,009,511 5,798,844 Total potential common shares excluded from the computation of diluted net loss per share 9,145,289 5,935,102

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Recent accounting pronouncements (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Operating lease ROU asset	$ 9,056	$ 9,376
Total operating lease liabilities	$ 9,730

FAIR VALUE MEASUREMENTS AND F_3

FAIR VALUE MEASUREMENTS AND FAIR VALUE OF FINANCIAL INSTRUMENTS - Marketable securities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Cash and Cash Equivalents	$ 10,555	$ 18,574
Level 2:
Short-term investments	273,738	289,424
Long-term investments	19,954	46,980
Fair Value, Measurements, Recurring
Total assets measured at fair value
Amortized Cost	304,194	354,693
Gross Unrealized Gains	436	321
Gross Unrealized Losses	383	36
Estimated Fair Value	304,247	354,978
Cash | Fair Value, Measurements, Recurring
Debt Securities, Available-for-sale [Line Items]
Cash and Cash Equivalents	2,257	1,393
Level 1:
Estimated Fair Value	2,257	1,393
Cash and Cash Equivalents | Fair Value, Measurements, Recurring
Debt Securities, Available-for-sale [Line Items]
Cash and Cash Equivalents	10,555	18,574
Cash and Cash Equivalents | Cash | Fair Value, Measurements, Recurring
Debt Securities, Available-for-sale [Line Items]
Cash and Cash Equivalents	2,257	1,393
Short-Term Investments | Fair Value, Measurements, Recurring
Level 2:
Short-term investments	273,738	289,424
Long-Term Investments | Fair Value, Measurements, Recurring
Level 2:
Long-term investments	19,954	46,980
Level 1: | Money market fund | Fair Value, Measurements, Recurring
Debt Securities, Available-for-sale [Line Items]
Cash and Cash Equivalents	8,298	17,181
Level 1:
Estimated Fair Value	8,298	17,181
Level 1: | Cash and Cash Equivalents | Money market fund | Fair Value, Measurements, Recurring
Debt Securities, Available-for-sale [Line Items]
Cash and Cash Equivalents	8,298	17,181
Level 2:
Level 2:
Gross Unrealized Losses	(383)	(36)
Level 2: | U.S. government agency securities
Level 2:
Gross Unrealized Losses	0	(14)
Level 2: | Commercial paper
Level 2:
Gross Unrealized Losses	0	(2)
Level 2: | Corporate debt securities
Level 2:
Gross Unrealized Losses	(383)	(20)
Level 2: | Fair Value, Measurements, Recurring
Level 2:
Amortized Cost	293,639	336,119
Gross Unrealized Gains	436	321
Gross Unrealized Losses	(383)	(36)
Estimated Fair Value	293,692	336,404
Level 2: | Fair Value, Measurements, Recurring | U.S. government agency securities
Level 2:
Amortized Cost	24,247	40,741
Gross Unrealized Gains	13	6
Gross Unrealized Losses	0	(14)
Estimated Fair Value	24,260	40,733
Level 2: | Fair Value, Measurements, Recurring | Commercial paper
Level 2:
Amortized Cost	83,255	108,248
Gross Unrealized Gains	300	107
Gross Unrealized Losses	0	(2)
Estimated Fair Value	83,555	108,353
Level 2: | Fair Value, Measurements, Recurring | Corporate debt securities
Level 2:
Amortized Cost	186,137	185,569
Gross Unrealized Gains	123	205
Gross Unrealized Losses	(383)	(20)
Estimated Fair Value	185,877	185,754
Level 2: | Fair Value, Measurements, Recurring | Asset-backed Securities [Member]
Level 2:
Amortized Cost		1,561
Gross Unrealized Gains		3
Gross Unrealized Losses		0
Estimated Fair Value		1,564
Level 2: | Cash and Cash Equivalents | Fair Value, Measurements, Recurring
Level 2:
Estimated Fair Value	0	0
Level 2: | Cash and Cash Equivalents | Fair Value, Measurements, Recurring | U.S. government agency securities
Level 2:
Estimated Fair Value	0	0
Level 2: | Cash and Cash Equivalents | Fair Value, Measurements, Recurring | Commercial paper
Level 2:
Estimated Fair Value	0	0
Level 2: | Cash and Cash Equivalents | Fair Value, Measurements, Recurring | Corporate debt securities
Level 2:
Estimated Fair Value	0	0
Level 2: | Cash and Cash Equivalents | Fair Value, Measurements, Recurring | Asset-backed Securities [Member]
Level 2:
Estimated Fair Value		0
Level 2: | Short-Term Investments | Fair Value, Measurements, Recurring
Level 2:
Short-term investments	273,738	289,424
Level 2: | Short-Term Investments | Fair Value, Measurements, Recurring | U.S. government agency securities
Level 2:
Short-term investments	21,505	19,990
Level 2: | Short-Term Investments | Fair Value, Measurements, Recurring | Commercial paper
Level 2:
Short-term investments	83,555	108,353
Level 2: | Short-Term Investments | Fair Value, Measurements, Recurring | Corporate debt securities
Level 2:
Short-term investments	168,678	159,517
Level 2: | Short-Term Investments | Fair Value, Measurements, Recurring | Asset-backed Securities [Member]
Level 2:
Short-term investments		1,564
Level 2: | Long-Term Investments | Fair Value, Measurements, Recurring
Level 2:
Long-term investments	19,954	46,980
Level 2: | Long-Term Investments | Fair Value, Measurements, Recurring | U.S. government agency securities
Level 2:
Long-term investments	2,755	20,743
Level 2: | Long-Term Investments | Fair Value, Measurements, Recurring | Commercial paper
Level 2:
Long-term investments	0	0
Level 2: | Long-Term Investments | Fair Value, Measurements, Recurring | Corporate debt securities
Level 2:
Long-term investments	$ 17,199	26,237
Level 2: | Long-Term Investments | Fair Value, Measurements, Recurring | Asset-backed Securities [Member]
Level 2:
Long-term investments		$ 0

FAIR VALUE MEASUREMENTS AND F_4

FAIR VALUE MEASUREMENTS AND FAIR VALUE OF FINANCIAL INSTRUMENTS - Additional information (Details)	3 Months Ended
	Mar. 31, 2020USD ($)position	Mar. 31, 2019USD ($)	Dec. 31, 2019position
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment interest income	$ 1,700,000	$ 1,600,000
Debt securities, available-for-sale, allowance for credit loss	$ 0
Debt instruments held in continuous unrealized loss position | position	33		18
Discount rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, measurement input	0.168
Discount rate | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, measurement input	0.168
Probability of the occurrence of certain events
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, measurement input	0.200
Probability of the occurrence of certain events | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, measurement input	0.200
Term Loan | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value	$ 52,700,000

FAIR VALUE MEASUREMENTS AND F_5

FAIR VALUE MEASUREMENTS AND FAIR VALUE OF FINANCIAL INSTRUMENTS - Available-for-sale investments in continuous unrealized loss position not deemed to be OTTI (Details) - Level 2 - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 103,083	$ 68,329
Unrealized Losses	(383)	(36)
U.S. government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	24,235
Unrealized Losses	0	(14)
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	5,426
Unrealized Losses	0	(2)
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	103,083	38,668
Unrealized Losses	$ (383)	$ (20)

FAIR VALUE MEASUREMENTS AND F_6

FAIR VALUE MEASUREMENTS AND FAIR VALUE OF FINANCIAL INSTRUMENTS - Maturities of cash equivalents and available-for-sale investments (Details) $ in Thousands	Mar. 31, 2020USD ($)
Amortized Cost
Mature in less than one year	$ 273,656
Mature in one to five years	19,983
Total	293,639
Fair Value
Mature in less than one year	273,738
Mature in one to five years	19,954
Total	$ 293,692

FAIR VALUE MEASUREMENTS AND F_7

FAIR VALUE MEASUREMENTS AND FAIR VALUE OF FINANCIAL INSTRUMENTS - Reconciliation of liabilities measured using Level 3 (Details) - Fair Value, Inputs, Level 3 - Compound Derivative Liability - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of period	$ 977	$ 161
Change in fair value	846	174
Fair value at end of period	$ 1,823	$ 335

FAIR VALUE MEASUREMENTS AND F_8

FAIR VALUE MEASUREMENTS AND FAIR VALUE OF FINANCIAL INSTRUMENTS - Significant unobservable inputs related to level 3 assets and liabilities (Details) $ in Thousands	Mar. 31, 2020USD ($)
Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative liability, measurement input	0.168
Probability of the occurrence of certain events
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative liability, measurement input	0.200
Fair Value, Inputs, Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Compound derivative liability	$ 1,823
Fair Value, Inputs, Level 3 | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative liability, measurement input	0.168
Fair Value, Inputs, Level 3 | Probability of the occurrence of certain events
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative liability, measurement input	0.200

LEASES - Information related to

LEASES - Information related to operating lease cost (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)	Mar. 31, 2019USD ($)	Sep. 01, 2020ft²	Dec. 31, 2019USD ($)	Aug. 15, 2019ft²	Aug. 14, 2019USD ($)ft²	Nov. 30, 2017ft²	Aug. 31, 2017ft²	Jul. 31, 2014
Lessee, Lease, Description [Line Items]
Term of operating lease									5 years
Operating lease renewal term									3 years
Lease rentable area (in square feet) | ft²								26,987
Extension of square footage leased | ft²						19,177
Temporary office space square footage | ft²					5,569
Term of third lease amendment lease						84 months
Term of operating lease not yet commenced						36 months
Operating lease ROU asset	$ 9,056			$ 9,376
Total operating lease liabilities	9,730
Operating lease, cost	500	$ 300
Variable lease cost	200	$ 200
Cash payments for operating leases	$ 300
Accounting Standards Update 2016-02
Lessee, Lease, Description [Line Items]
Operating lease ROU asset						$ 8,100
Total operating lease liabilities						$ 8,100
Amended Lease
Lessee, Lease, Description [Line Items]
Lease rentable area (in square feet) | ft²								13,258
Second Amendment To Lease
Lessee, Lease, Description [Line Items]
Lease rentable area (in square feet) | ft²							26,897
Forecast
Lessee, Lease, Description [Line Items]
Lease rentable area (in square feet) | ft²			46,074

LEASES - Operating lease schedu

LEASES - Operating lease schedule of maturity (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)
Leases [Abstract]
2020 (remaining nine months)	$ 835
2021	1,377
2022	1,662
2023	1,712
2024	1,763
2025 and thereafter	4,959
Total lease payments	12,308
Less: imputed interest	(2,578)
Total operating lease liabilities	9,730
Future minimum payments of operating lease	$ 8,200
Term of operating lease not yet commenced, second expansion premises	7 years

LEASES - Supplemental balance s

LEASES - Supplemental balance sheet information regarding operating leases (Details)	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Leases [Abstract]
Weighted average discount rate	6.00%		8.00%
Weighted average remaining lease term	7 years 4 months 24 days	2 years 3 months 18 days

OTHER BALANCE SHEET COMPONENT_2

OTHER BALANCE SHEET COMPONENTS - Property and equipment, net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 4,298		$ 5,376
Less: accumulated depreciation and amortization	(2,878)		(2,648)
Total property and equipment, net	1,420		2,728
Depreciation and amortization expense	230	$ 172
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	274		265
Computer and lab equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	2,780		3,867
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,244		$ 1,244

OTHER BALANCE SHEET COMPONENT_3

OTHER BALANCE SHEET COMPONENTS - Accrued expense and other current liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued clinical and nonclinical study costs	$ 11,599	$ 8,343
Accrued contract manufacturing	18,287	17,343
Accrued compensation	3,583	3,367
Accrued professional fees and other	6,594	3,727
Total accrued expenses and other current liabilities	$ 40,063	$ 32,780

BORROWINGS - Additional informa

BORROWINGS - Additional information (Details)	Mar. 27, 2019USD ($)$ / sharesshares	Jun. 30, 2019	Dec. 31, 2019USD ($)$ / sharesshares	Mar. 31, 2020USD ($)	Mar. 31, 2019USD ($)	Dec. 28, 2018USD ($)$ / sharesshares	Oct. 15, 2018USD ($)tranche	Apr. 10, 2018USD ($)	Feb. 28, 2018USD ($)tranche$ / sharesshares
Debt Instrument [Line Items]
Long-term portion of Term Loan			$ 58,374,000	$ 59,125,000
Percentage of principal	1.00%
Term Loan
Debt Instrument [Line Items]
Debt aggregate principal amount							$ 100,000,000		$ 100,000,000
Debt, number of tranches | tranche							5		5
Long-term portion of Term Loan	$ 40,000,000
Debt payment terms, multiplier	7.55%
Number of shares called by warrant (in shares) | shares									53,458
Exercise price of warrant (in USD per share) | $ / shares									$ 9.35
Estimated fair value of warrants									$ 200,000
Increase (decrease) in equity due to warrants						$ 900,000		$ 200,000
Fair value of embedded derivative liability				1,800,000				$ 700,000
Unamortized issuance costs and debt discounts				3,300,000	$ 3,600,000
Term Loan | Minimum
Debt Instrument [Line Items]
Debt prepayment fee, percentage	2.00%
Term Loan | Tranche one
Debt Instrument [Line Items]
Debt aggregate principal amount									25,000,000
Term Loan | Tranche two
Debt Instrument [Line Items]
Debt aggregate principal amount							$ 15,000,000		$ 25,000,000
Number of shares called by warrant (in shares) | shares						53,458
Exercise price of warrant (in USD per share) | $ / shares						$ 9.35
New Term Loan
Debt Instrument [Line Items]
Maximum borrowing capacity of term loan	$ 200,000,000
Term of principal and interest payments	30 months
One time payment of principal	$ 2,600,000
Debt prepayment fee, percentage year two	1.50%
Debt prepayment fee, percentage year three	1.00%
Debt prepayment fee, percentage after year three	0.00%
New Term Loan | Maximum
Debt Instrument [Line Items]
Extended period for payment of interest only	24 months
New Term Loan | Tranche one
Debt Instrument [Line Items]
Debt aggregate principal amount	$ 20,000,000
New Term Loan | Tranche two
Debt Instrument [Line Items]
Debt aggregate principal amount				15,000,000
New Term Loan | Tranche three
Debt Instrument [Line Items]
Debt aggregate principal amount	75,000,000
New Term Loan | Tranche four
Debt Instrument [Line Items]
Debt aggregate principal amount	$ 50,000,000
New Term Loan | Tranche four | Hercules Capital, Inc. [Member]
Debt Instrument [Line Items]
Debt aggregate principal amount				5,000,000
New Term Loan | Tranche four | Hercules Technology III, L.P. [Member]
Debt Instrument [Line Items]
Debt aggregate principal amount				$ 10,000,000
Third Amendment to Term Loan
Debt Instrument [Line Items]
Number of shares called by warrant (in shares) | shares	16,721		8,361
Exercise price of warrant (in USD per share) | $ / shares	$ 23.92		$ 23.92
Increase (decrease) in equity due to warrants	$ 300,000		$ 300,000
Floating variable rate 1 | Term Loan
Debt Instrument [Line Items]
Debt interest rate			8.35%
Floating variable rate 2 | Term Loan | Prime rate
Debt Instrument [Line Items]
Debt, basis spread on variable rate		8.35%
Floating variable rate 2 | New Term Loan | Prime rate
Debt Instrument [Line Items]
Debt, basis spread on adjusted variable rate	6.00%
Floating variable rate 3 | Term Loan
Debt Instrument [Line Items]
Debt interest rate			9.85%
Time To Liquidity | Third Amendment to Term Loan
Debt Instrument [Line Items]
Measurement input, time to liquidity	7 years		7 years
Volatility | Third Amendment to Term Loan
Debt Instrument [Line Items]
Warrants measurement input	0.750		0.727
Risk-free interest rate | Third Amendment to Term Loan
Debt Instrument [Line Items]
Warrants measurement input	0.023		0.018
Discount Rate
Debt Instrument [Line Items]
Derivative liability, measurement input				0.168
Measurement input, probability of occurrence of certain events
Debt Instrument [Line Items]
Derivative liability, measurement input				0.200

BORROWINGS - Debt maturity sche

BORROWINGS - Debt maturity schedule (Details) $ in Thousands	Mar. 31, 2020USD ($)
Debt Disclosure [Abstract]
2020 (remaining nine months)	$ 3,828
2021	21,259
2022	26,675
2023	19,893
Long-term debt including interest payable	71,655
Less: amount representing interest	(11,655)
Present value of Term Loan	60,000
Less: current portion	0
Long-term portion of Term Loan	$ 60,000

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details) $ in Thousands	Mar. 31, 2020USD ($)
Lease obligations
2020	$ 1,037
2021 - 2022	5,018
2023 - 2024	5,953
Thereafter	8,494
Manufacturing and service contracts
2020	51,131
2021 - 2022	83,107
2023 - 2024	113,202
Thereafter	339,606
Total contractual obligations and commitments
Total	679,320
2020	56,066
2021 - 2022	136,106
2023 - 2024	139,048
Thereafter	348,100
Term Loan
Term loan and tenant improvement loan
Total	71,655
2020	3,828
2021 - 2022	47,934
Long-term Debt, Maturing in Years Four and Five	19,893
Thereafter	0
Lease obligations
Total	20,502
Tenant Improvement Loan
Term loan and tenant improvement loan
Total	117
2020	70
2021 - 2022	47
Long-term Debt, Maturing in Years Four and Five	0
Thereafter	0
Manufacturing and service contracts
Total	$ 587,046

STOCKHOLDERS' EQUITY - Addition

STOCKHOLDERS' EQUITY - Additional information (Details) - USD ($) $ / shares in Units, $ in Millions	Apr. 08, 2019	Mar. 31, 2020	Dec. 31, 2019	Jul. 02, 2018
Class of Stock [Line Items]
Total number of shares authorized for issue (in shares)				440,000,000
Common stock, shares authorized (in shares)		400,000,000	400,000,000	400,000,000
Common stock, par value (in USD per share)		$ 0.001	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)		40,000,000	40,000,000	40,000,000
Preferred stock, par value (in USD per share)		$ 0.001	$ 0.001	$ 0.001
Common stock, shares outstanding (in shares)		49,913,232	49,763,176
Common stock, shares issued (in shares)		49,913,232	49,913,232
Preferred stock, outstanding (in shares)		0	0
Over-Allotment Option
Class of Stock [Line Items]
Number of common stock issued (in shares)	840,000
Underwritten Public Offering
Class of Stock [Line Items]
Number of common stock issued (in shares)	6,440,000
Share price (in USD per share)	$ 36
Proceeds from initial public offering, net of issuance costs	$ 217.9
Underwriting discounts and commissions	$ 13.9

STOCKHOLDERS' EQUITY - Common s

STOCKHOLDERS' EQUITY - Common stock (Details) - shares	Mar. 31, 2020	Dec. 31, 2019
Equity [Abstract]
Stock options and RSUs issued and outstanding (in shares)	9,009,511	6,809,257
Stock options, RSUs and ESPP shares authorized for future issuance (in shares)	3,395,164	3,257,316
Total (in shares)	12,404,675	10,066,573

NET LOSS PER SHARE - Basic and

NET LOSS PER SHARE - Basic and diluted net loss per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Numerator:
Net loss	$ (74,114)	$ (37,897)
Denominator:
Weighted average common shares outstanding (in shares)	49,845,621	42,283,526
Less: weighted average shares subject to repurchase (in shares)	(4,214)	(15,464)
Weighted-average number of shares used in basic and diluted net loss per share (in shares)	49,841,407	42,268,062
Net loss per share, basic and diluted (in USD per share)	$ (1.49)	$ (0.90)

NET LOSS PER SHARE - Antidiluti

NET LOSS PER SHARE - Antidilutive securities (Details) - shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	9,145,289	5,935,102
Warrants to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	131,998	123,637
Common stock subject to repurchase
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	3,780	12,621
Options and RSUs issued and outstanding
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	9,009,511	5,798,844