CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities
Net loss	$ (68,754)	$ (79,483)
Adjustment to reconcile net loss to net cash used in operating activities
Stock-based compensation	5,081	135
Depreciation and amortization	1,558	2,123
Impairment loss charged	0	1,590
Loss from disposal of property and equipment	31	0
(Income) Loss from equity in unconsolidated joint venture	(127)	178
Interest expense of convertible notes recognized	23,706	49,708
Loss on extinguishment of convertible notes	0	6,111
Provision for firm purchase commitment	1,585	0
Change in fair value, embedded derivative	(2,092)	716
Change in fair value, Sponsor Earnout Shares	8,083	0
Other	0	(52)
Changes in operating assets and liabilities:
Receivable on sale of state tax attributes	4,060	(4,060)
Prepaid and other assets	(1,607)	(462)
Inventory	(214)	634
Grants receivable	195	352
Vendor deposits	(593)	109
Security deposit	(17)	(64)
Accounts payable and accrued expenses	1,709	(2,210)
Accounts payable and accrued expenses-related parties	1,323	1,140
Contract liabilities	(223)	(468)
Deferred rent	99	169
Other assets	(362)	0
Net cash used in operating activities	(26,559)	(23,834)
Cash flows from investing activities
Investment in joint venture	(3,020)	(601)
Purchases of property and equipment	(3,605)	(2,299)
Net cash used in investing activities	(6,625)	(2,900)
Cash flows from financing activities
Capital lease payments	(15)	(72)
Proceeds from issuance of convertible notes payable – related party	9,009	19,346
Proceeds of short term notes payable	191	0
Repayment of short term notes payable	(97)	(1,000)
Proceeds from Paycheck Protection Program loan	1,257	0
Proceeds attributable to beneficial conversion features of convertible notes payable – related party	0	1,793
Proceeds from capital infusion in reverse recapitalization	142,345	0
Transaction cost for the reverse recapitalization	(10,274)	0
Issuance of contingently redeemable preferred units	11,759	2,031
Net cash provided by financing activities	154,175	22,098
Net increase (decrease) in cash and cash equivalents	120,991	(4,636)
Cash and cash equivalents, beginning of year	862	5,498
Cash and cash equivalents, end of year	121,853	862
Non-cash Investing and Financing Activities
Contribution of inventory to joint venture	0	167
Accrued and unpaid capital expenditures	374	93
Conversion of convertible notes to common stock in connection with merger	108,863	0
Conversion of contingently redeemable preferred stock to common stock in connection with merger	121,125	0
Receivable from disgorgement of short swing profits	432	0
Supplemental disclosures
Cash paid for interest	$ 118	$ 6