Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net loss	$ (49,121)	$ (40,817)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation and amortization	2,172	2,053
Reduction of operating lease right-of-use (“ROU”) assets	670	787
Stock-based compensation	4,938	11,530
Reduction of revenue related to stock warrant granted to a customer	5,303	0
Provision for doubtful accounts	0	1,682
Amortization of investment premium or discount, net	427	0
Other	(1)	161
Changes in operating assets and liabilities:
Accounts receivable, net	1,347	(1,172)
Inventories, net	(3,199)	(2,762)
Prepaid and other current assets	2,249	1,702
Contract assets	3,262	(2,438)
Other assets	41	(2)
Accounts payable	2,114	(3,856)
Accrued expenses and other liabilities	(3,832)	(3,867)
Contract liabilities	(1,677)	1,892
Net cash used in operating activities	(35,307)	(35,107)
Cash flows from investing activities:
Purchase of property, plant and equipment and intangibles	(1,545)	(601)
Proceeds from sales of short-term investments	14,499	2,000
Proceeds from maturities of short-term investments	64,750	7,000
Purchase of short-term investments	(35,358)	(91,932)
Net cash provided by (used in) investing activities	42,346	(83,533)
Cash flows from financing activities:
Payment of transaction costs related to Business Combination	0	(20,006)
Proceeds from warrant exercises, net of issuance costs	0	89,222
Tax withholding payment for vested equity awards	0	(37)
Net cash provided by financing activities	0	69,179
Effect of exchange rate fluctuations on cash and cash equivalents	16	18
Net increase (decrease) in cash and cash equivalents	7,055	(49,443)
Beginning cash and cash equivalents	24,064	204,648
Ending cash and cash equivalents	31,119	155,205
Supplemental disclosures of cash flow information:
Cash paid for interest	3	36
Cash paid for income taxes, net	407	333
Cash paid for operating leases	883	1,119
Supplemental disclosure of noncash investing and financing activities:
Changes in accrued purchases of property, plant and equipment, and intangibles	791	105
ROU assets obtained in exchange for new operating lease liabilities	55	340
Transaction costs included in accrued liabilities	$ 0	$ 5,000