CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities:
Net loss	$ (114,526)	$ (79,124)
Adjustments to reconcile net loss to net cash used in operating activities
Stock-based compensation	17,624	14,697
Depreciation and amortization	4,729	740
Deferred income taxes	0	(17,425)
Amortization of debt discount and issuance costs	4,281	0
Acquired in-process research and development expense	0	3,000
Change in fair value of contingent consideration	1,100	4,300
Other non-cash items, net	573	77
Changes in operating assets and liabilities:
Accounts receivable	(3,878)	0
Inventory	(1,897)	(475)
Prepaid expenses and other current assets	(272)	251
Other non-current assets	(50)	(1,171)
Accounts payable, accrued and other current liabilities	(2,649)	(5,737)
Operating lease liabilities	(723)	(634)
Deferred revenue	(1,102)	(2,281)
Net cash used in operating activities	(96,790)	(83,782)
Cash flows from investing activities:
Cash paid for in-process research and development asset	0	(3,000)
Purchases of marketable securities	(214,547)	(180,832)
Proceeds from maturities of marketable securities	284,945	114,205
Proceeds from sale of marketable securities	13,500	2,988
Purchases of property and equipment	(87)	(415)
Net cash (used in) provided by investing activities	83,811	(67,054)
Cash flows from financing activities:
Payment of contingent consideration	(15,000)	0
Proceeds from issuance of common stock under equity incentive plans	1,042	4,498
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	(14,854)	225,637
Net (decrease) increase in cash and cash equivalents	(27,833)	74,801
Cash and cash equivalents, beginning of the period	166,916	62,070
Cash and cash equivalents, end of the period	139,083	136,871
Supplemental disclosure of non-cash investing and financing activities:
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 0	$ 1,156