Balance Sheet Components - Property and Equipment, net (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Property and Equipment, net
Total property and equipment	$ 1,829,000	$ 1,762,000
Less: Accumulated depreciation	(823,000)	(491,000)
Property and equipment, net	1,006,000	1,271,000
Depreciation expense	332,000	278,000
Lab equipment
Property and Equipment, net
Total property and equipment	1,804,000	1,737,000
Computer equipment and software
Property and Equipment, net
Total property and equipment	$ 25,000	$ 25,000