Condensed Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues	$ 639	$ 1,190	$ 2,695	$ 4,281
Operating expenses:
Total cost of revenue	0	2,072	1,398	5,138
Gross profit	639	(882)	1,297	(857)
Research and development expense	1,972	3,566	7,262	15,484
Sales, marketing, general and administrative expense	1,485	1,697	4,536	6,851
Gain on disposal of fixed assets	0	0	(450)	0
Total operating expenses	3,457	5,263	11,348	22,335
Loss from operations	(2,818)	(6,145)	(10,051)	(23,192)
Other expense, net	(8)	4	(13)	(7)
Net loss	$ (2,826)	$ (6,141)	$ (10,064)	$ (23,199)
Net loss per share - basic and diluted	$ (0.02)	$ (0.05)	$ (0.07)	$ (0.21)
Weighted-average shares outstanding - basic and diluted	143,685,000	114,874,000	137,027,000	107,953,000
Product revenue
Revenue from Contract with Customer, Including Assessed Tax	$ 100	$ 999	$ 1,347	$ 1,198
Operating expenses:
Cost of Goods and Services Sold	0	2,039	1,394	3,352
License and royalty
Revenue from Contract with Customer, Including Assessed Tax	539	17	1,323	17
Operating expenses:
Cost of Goods and Services Sold	0
Contract
Revenue from Contract with Customer, Including Assessed Tax	0	174	25	3,066
Operating expenses:
Cost of Goods and Services Sold	$ 0	$ 33	$ 4	$ 1,786