Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Cash flows from operating activities:
Net loss	$ (7,074)	$ (11,475)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	709	704
Amortization of right-of-use assets	464	427
Amortization of intangible assets	71	69
Amortization of debt discount and deferred financing fees	219	220
(Recovery of) provision for bad debt	(267)	267
Provision for inventory write-down	581	459
Change in fair value of derivatives	185	(252)
Investment (gains) loss	(426)	96
Stock-based compensation	2,954	2,678
Change in operating assets and liabilities:
Accounts receivable	175	(624)
Inventory	(1,525)	(1,166)
Prepaid expenses and other	(509)	(1,030)
Accounts payable and accrued expenses	(2,442)	(1,104)
Operating lease obligations	(537)	(320)
Cash paid for interest portion of finance leases	(1)	0
Net cash used in operating activities	(7,423)	(11,051)
Cash flows from investing activities:
Purchase of property and equipment	(4,304)	(5,037)
Purchase of investments	(10,203)	(6,024)
Proceeds from sale of investments	13,974	4,400
Cash payments for intangible assets	(253)	(580)
Net cash used in investing activities	(786)	(7,241)
Cash flows from financing activities:
Cash paid for debt portion of finance leases	(1)	(2)
Proceeds from exercise of stock options and ESPP stock purchases	634	97
Net cash provided by financing activities	633	95
Net decrease in cash, cash equivalents, and restricted cash	(7,576)	(18,197)
Cash, cash equivalents, and restricted cash, beginning of period	21,535	39,007
Cash, cash equivalents, and restricted cash, end of period	13,959	20,810
Supplemental disclosures of cash flow activity:
Cash paid for interest, net of capitalized interest	0	0
Supplemental disclosure of non-cash investing and financing activities:
Acquisition of fixed assets in accounts payable and accrued expenses	1,026	1,119
Obtaining a right-of-use asset in exchange for a lease liability	0	641
Acquisition of intangible assets in accounts payable and accrued expenses	$ 326	$ 239