Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities
Net loss	$ (43,200,000)	$ (13,634,000)	$ (26,483,000)
Adjustments to reconcile net loss to net cash used in operations:
Depreciation and amortization	1,464,000	963,000	1,649,000
Impairment of intangible assets			160,000
Impairment of property and equipment	882,000		434,000
Gain on disposal of property and equipment		(450,000)
Share-based compensation expense	15,284,000	1,297,000	1,614,000
Non-cash interest income (expense)	(10,000)	11,000
Inventory write-downs	48,000	168,000	2,203,000
Net accretion of premium on short-term investments	86,000
Gain on debt extinguishment	(692,000)
Change in:
Accounts receivable		1,079,000	(603,000)
Costs and estimated earnings in excess of billings on uncompleted contracts			987,000
Inventory	(1,828,000)	24,000	(1,286,000)
Other current and non-current assets	(2,552,000)	154,000	1,866,000
Accounts payable	2,520,000	(1,387,000)	(268,000)
Accrued liabilities	675,000	(1,550,000)	(3,379,000)
Deferred revenue		(21,000)	21,000
Contract liabilities and other current liabilities	(1,319,000)	(2,073,000)	(316,000)
Operating lease liabilities	(762,000)	(656,000)	(642,000)
Net cash used in operating activities	(29,404,000)	(16,075,000)	(24,043,000)
Cash flows from investing activities
Purchases of investment securities	(32,825,000)
Proceeds on sale of property and equipment		525,000
Purchases of property and equipment	(2,493,000)	(402,000)	(745,000)
Net cash provided by (used in) investing activities	(35,318,000)	123,000	(745,000)
Cash flows from financing activities
Principal payments under finance leases	(28,000)	(29,000)	(20,000)
Proceeds from long-term debt		1,571,000
Principal payments under long-term debt	(488,000)
Payments received on subscriptions receivable	6,135,000
Proceeds from stock option exercises	2,654,000	1,000,000
Net proceeds from issuance of common stock	122,891,000	24,435,000	16,879,000
Net cash provided by financing activities	131,164,000	26,977,000	16,859,000
Change in cash, cash equivalents, and restricted cash	66,442,000	11,025,000	(7,929,000)
Cash, cash equivalents, and restricted cash at beginning of period	17,297,000	6,272,000	14,201,000
Cash, cash equivalents, and restricted cash at end of period	83,739,000	17,297,000	6,272,000
Supplemental schedule of non-cash investing and financing activities
Issuance of common stock for subscriptions receivable		6,135,000
Property and equipment acquired under finance leases		70,000
Lease liabilities from obtaining right-of-use operating asset	5,097,000
Non-cash additions to property and equipment	550,000	116,000	37,000
Issuance of common stock for commitment fee			$ 535,000