Condensed Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues	$ 587	$ 1,240	$ 2,056	$ 3,091
Operating expenses:
Total cost of revenue	(1)	1,823	1,398	3,066
Gross profit	588	(583)	658	25
Research and development expense	1,607	5,945	5,290	11,918
Sales, marketing, general and administrative expense	1,280	2,455	3,051	5,154
Gain on disposal of fixed assets	0	0	(450)	0
Total operating expenses	2,887	8,400	7,891	17,072
Loss from operations	(2,299)	(8,983)	(7,233)	(17,047)
Other expense, net	(5)	(7)	(5)	(11)
Net loss	$ (2,304)	$ (8,990)	$ (7,238)	$ (17,058)
Net loss per share - basic and diluted	$ (0.02)	$ (0.08)	$ (0.05)	$ (0.16)
Weighted-average shares outstanding - basic and diluted	140,107,000	106,872,000	133,661,000	104,435,000
Product revenue
Revenue from Contract with Customer, Including Assessed Tax	$ 0	$ 0	$ 1,247	$ 199
Operating expenses:
Cost of Goods and Services Sold	(1)	1,025	1,394	1,313
License and royalty
Revenue from Contract with Customer, Including Assessed Tax	572	0	784	0
Contract
Revenue from Contract with Customer, Including Assessed Tax	15	1,240	25	2,892
Operating expenses:
Cost of Goods and Services Sold	$ 0	$ 798	$ 4	$ 1,753