Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 57,144	$ 204,648
Short-term investments	267,395	145,636
Accounts receivable, net	9,576	13,979
Inventories, net	11,860	18,132
Prepaid and other current assets	10,862	22,319
Total current assets	356,837	404,714
Property, plant and equipment, net	14,088	16,805
Goodwill	1,189	1,189
Intangible assets, net	338	627
Contract assets	10,148	8,440
Other assets	19,274	937
Total assets	401,874	432,712
Current liabilities:
Accounts payable	4,325	7,721
Accrued expense and other current liabilities	32,793	50,349
Contract liabilities	7,609	7,323
Total current liabilities	44,727	65,393
Long-term tax liabilities	563	569
Other long-term liabilities	28,950	25,927
Total liabilities	74,240	91,889
Commitments and contingencies (Note 15)
Stockholders’ equity:
Preferred stock	0	0
Common stock	20	18
Additional paid-in capital	816,710	656,717
Accumulated other comprehensive loss	(233)	(230)
Accumulated deficit	(488,863)	(315,682)
Total stockholders’ equity	327,634	340,823
Total liabilities and stockholders’ equity	$ 401,874	$ 432,712