CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenue	$ 1,082	$ 0	$ 0
Cost of revenue	594	0	0
Gross profit	488	0	0
Operating expenses:
Research and development	67,025	72,062	46,575
Selling, general and administrative	44,634	42,296	50,333
Goodwill impairment	0	9,483	0
Total operating expenses	111,659	123,841	96,908
Loss from operations	(111,171)	(123,841)	(96,908)
Interest expense, net	0	0	(5)
Dividend income	9,536	5,301	2,549
Gain (loss) on marketable securities, net	5,587	(20,603)	(5,023)
Change in fair value of warrant liabilities	(278)	6,243	4,379
Other income, net	366	458	19
Loss before provision for income taxes	(95,960)	(132,442)	(94,989)
Provision for income taxes	0	0	0
Net loss	(95,960)	(132,442)	(94,989)
Comprehensive loss	$ (95,960)	$ (132,442)	$ (94,989)
Net loss per common share attributable to common stockholders, basic (in dollars per share)	$ (0.68)	$ (0.95)	$ (1.19)
Net loss per common share attributable to common stockholders, diluted (in dollars per share)	$ (0.68)	$ (0.95)	$ (1.19)
Weighted-average shares used to compute net loss per share attributable to common stockholders, basic (in shares)	141,300	139,255	79,579
Weighted-average shares used to compute net loss per share attributable to common stockholders, diluted (in shares)	141,300	139,255	79,579
Product [Member]
Revenue	$ 1,031	$ 0	$ 0
Service [Member]
Revenue	$ 51	$ 0	$ 0