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	$ (20,958)	$ (66,611)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	37	906
Stock-based compensation	2,851	4,432
Amortization of debt issuance costs	14	362
Changes in operating assets and liabilities:
(Increase) decrease in accounts receivable	294	26,397
(Increase) decrease in inventory	0	96
(Increase) decrease in prepaid expenses and other current assets	1,095	(2,875)
Decrease in other assets	(74)	102
Decrease in accounts payable and other liabilities	(8,418)	15,137
Net cash provided by (used in) operating activities	(25,159)	(22,054)
Cash flows from investing activities:
Purchases of property and equipment	(38)	0
Purchases of investments	(21,686)	(33,222)
Maturities of investments	4,000	76,000
Net cash (used in) provided by investing activities	(17,724)	42,778
Cash flows from financing activities:
Proceeds from issuance of common stock	16,947	0
Repurchase of common stock	(2,675)	(923)
Repayment of debt borrowings, net of fees	0	(321)
Net cash used in financing activities	14,272	(1,244)
Net increase (decrease) in cash and cash equivalents	(28,611)	19,480
Cash and cash equivalents at beginning of period	126,263	36,112
Cash and cash equivalents at end of period	97,652	55,592
Supplemental disclosure of cash flow information:
Cash paid for interest	0	$ 3,658
Initial recognition of right of use asset	1,700
Operating Lease, Right-of-Use Asset	2,900
Issuance of common stock under Equity Incentive Plans, value	$ 16,399