Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current Assets:
Cash and cash equivalents	$ 6,995	$ 17,096
Short-term investments, available-for-sale	994	3,971
Accounts receivable, net	675	3,508
Inventories	5,958	7,172
Prepaid expenses	3,314	3,143
Other current assets	1,312	1,496
Total Current Assets	19,248	36,386
Restricted cash	1,483	1,642
Inventories, net of current portion	3,954	4,043
Property and equipment, net	8,630	8,959
Intellectual property, net	1,114	1,237
Net deferred tax assets	37	44
Operating lease right-of-use assets, net	4,926	5,165
Other long-term assets	1,422	1,610
Total Assets	40,814	59,086
Current Liabilities:
Accounts payable	4,036	4,145
Accrued employee compensation and benefits	3,814	5,390
Accrued expenses and other current liabilities	1,243	1,636
Contingent consideration, current	8,700	0
Operating lease liabilities, current	1,056	1,036
Deferred revenue	439	421
Total Current Liabilities	19,288	12,628
Long-Term Liabilities:
Deferred revenue - less current portion	330	290
Contingent consideration	0	2,220
Warrant liabilities	3,772	5,888
Noncurrent operating lease liabilities	4,400	4,646
Total Liabilities	27,790	25,672
Commitments and Contingencies
Stockholders' Equity:
Common stock $0.001 par value, 750,000,000 shares authorized at March 31, 2024 and December 31, 2023; 271,986,369 and 264,921,526 issued and outstanding at March 31, 2024 and December 31, 2023, respectively	272	265
Preferred stock, $0.01 par value, 25,000,000 shares authorized, no shares issued and outstanding at March 31, 2024 and December 31, 2023	0	0
Additional paid-in capital	975,715	973,129
Accumulated deficit	(961,865)	(939,368)
Accumulated other comprehensive loss	(1,098)	(612)
Total Stockholders' Equity	13,024	33,414
Total Liabilities and Stockholders' Equity	40,814	59,086
Intellectual Property [Member]
Current Assets:
Intellectual property, net	$ 1,114	$ 1,237