Deferred Revenue - Summary of Deferred Revenue Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Movement in Deferred Revenue [Roll Forward]
Balance at beginning of period	$ 1,212	$ 2,495
Cash Received NIH	2,400	1,000
Converted to Equity		(1,600)
Recognized as revenue	(2,694)	(683)
Balance at end of period	918	1,212
NIH Grant
Movement in Deferred Revenue [Roll Forward]
Balance at beginning of period	568	0
Cash Received NIH	2,400	1,000
Converted to Equity		0
Recognized as revenue	(2,050)	(432)
Balance at end of period	918	568
BED
Movement in Deferred Revenue [Roll Forward]
Balance at beginning of period	644	895
Cash Received NIH	0	0
Converted to Equity		0
Recognized as revenue	(644)	(251)
Balance at end of period	$ 0	$ 644