Balance Sheets - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 20,210,000	$ 55,358,000
Short-term investments	161,264,000	158,316,000
Accounts receivable, net of allowances of $26 and $3 at December 31, 2023 and December 31, 2022, respectively	23,573,000	18,007,000
Inventories	29,876,000	19,293,000
Prepaid expenses and other current assets	5,912,000	3,924,000
Total current assets	240,835,000	254,898,000
Long-term investments	9,456,000
Property and equipment, net	8,114,000	9,372,000
Restricted cash	0	155,000
Other non-current assets	6,904,000	5,260,000
Total assets	265,309,000	269,685,000
Current liabilities:
Accounts payable	5,676,000	2,523,000
Accrued liabilities	24,607,000	21,965,000
Total current liabilities	30,283,000	24,488,000
Long-term debt	75,626,000	74,596,000
Other liabilities	8,249,000	6,726,000
Total liabilities	114,158,000	105,810,000
Commitments and contingencies (Note 7)
Stockholders' equity:
Preferred stock, $0.001 par value Shares authorized: 5,000,000 at December 31, 2023 and 2022 Shares issued and outstanding: none at December 31, 2023 and 2022
Common stock, $0.001 par value Shares authorized: 100,000,000 at December 31, 2023 and 2022 Shares issued and outstanding: 39,165,481 and 38,355,972 at December 31, 2023 and 2022, respectively	39,000	38,000
Additional paid-in capital	550,495,000	507,715,000
Accumulated other comprehensive income (loss)	72,000	(166,000)
Accumulated deficit	(399,455,000)	(343,712,000)
Total stockholders’ equity	151,151,000	163,875,000
Total liabilities and stockholders’ equity	$ 265,309,000	$ 269,685,000