Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current Assets:
Cash and cash equivalents	$ 10,844	$ 18,129
Short-term investments, available-for-sale	83,360	80,262
Accounts receivable, net	699	749
Inventories	8,451	8,634
Prepaid expenses	2,927	3,255
Employee retention tax credit receivable	1,147	1,311
Other current assets	1,134	957
Total Current Assets	108,562	113,297
Restricted cash	1,290	1,154
Long-term investments, available-for-sale	9,581	37,435
Inventories, net of current portion	7,258	7,074
Property and equipment, net	9,389	10,971
Intellectual property, net	4,122	9,892
Net deferred tax assets	244	288
Operating lease right-of-use assets, net	4,747	5,348
Other long-term assets	2,157	1,014
Total Assets	147,350	186,473
Current Liabilities:
Accounts payable	3,849	3,448
Accrued employee compensation and benefits	3,127	3,559
Accrued expenses and other current liabilities	1,617	1,617
Operating lease liabilities - current portion	579	683
Deferred revenue	510	543
Total Current Liabilities	9,682	9,850
Long-Term Liabilities:
Contingent consideration	1,619	2,371
Noncurrent operating lease liabilities	4,610	5,006
Total Liabilities	15,911	17,227
Commitments and Contingencies (Note 14)
Stockholders' Equity:
Common stock $0.001 par value, 750,000,000 shares authorized at June 30, 2022 and December 31, 2021; 236,620,415 and 235,218,552 shares issued and outstanding at June 30, 2022 and December 31, 2021, respectively	237	235
Preferred stock, $0.01 par value, 25,000,000 shares authorized, no shares issued and outstanding at June 30, 2022 and December 31, 2021	0	0
Additional paid-in capital	958,646	954,649
Accumulated deficit	(824,121)	(785,374)
Accumulated other comprehensive loss	(3,323)	(264)
Total Stockholders' Equity	131,439	169,246
Total Liabilities and Stockholders' Equity	147,350	186,473
Intellectual Property [Member]
Current Assets:
Intellectual property, net	$ 4,122	$ 9,892