CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities:
Net loss	$ (55,630)	$ (25,800)
Adjustments to reconcile net loss to net cash used in operating activities
Stock-based compensation	8,098	6,394
Depreciation and amortization	2,365	357
Amortization of debt discount and issuance costs	2,098	0
Acquired in-process research and development expense	0	1,500
Change in fair value of contingent consideration	600	(7,900)
Other non-cash items, net	236	(38)
Changes in operating assets and liabilities:
Accounts receivable	(2,295)	0
Inventory	(1,298)	0
Prepaid expenses and other current assets	1,150	(20,463)
Other non-current assets	108	(405)
Accounts payable, accrued and other current liabilities	(9,010)	(4,435)
Operating lease liabilities	(444)	(452)
Deferred revenue	164	(1,249)
Net cash used in operating activities	(53,858)	(52,491)
Cash flows from investing activities:
Cash paid for in-process research and development asset	0	(1,500)
Purchases of marketable securities	(141,652)	(15,695)
Proceeds from sale and maturities of marketable securities	130,888	54,605
Purchases of property and equipment	(87)	(193)
Net cash (used in) provided by investing activities	(10,851)	37,217
Cash flows from financing activities:
Payment of contingent consideration	(15,000)	0
Proceeds from issuance of common stock under equity incentive plans	6	2,040
Payments of tax withholding obligation on vesting restricted stock units	(896)	(569)
Proceeds from issuance of common stock, net of issuance costs	0	221,708
Net cash (used in) provided by financing activities	(15,890)	223,179
Net (decrease) increase in cash and cash equivalents	(80,599)	207,905
Cash and cash equivalents, beginning of the period	166,916	62,070
Cash and cash equivalents, end of the period	86,317	269,975
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 0	$ 1,156