Income Taxes - Reconciliation of Income taxes Provided at Federal Statutory Rate to Actual Income Tax Provision (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income tax benefit computed at U.S. statutory rate	$ (794)	$ (542)
Research and development credits	(66)	(170)
Amortization of intangible assets	(60)	(60)
Goodwill impairment		17
Valuation allowance changes affecting tax provision	919	752
Other	$ 1	3
Income tax provision		$ 0