Income Taxes - Tax provision (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Taxes
Loss before provision for income taxes	$ (33,809,000)	$ (38,529,000)
Current:
Federal		10,000
Total current		10,000
Deferred:
Total deferred	$ 0	0
Total provision for income taxes		$ 10,000
Effective tax rate, differed from the federal statutory rate
Statutory rate	(21.00%)	(21.00%)
State taxes		(0.10%)
Book loss on debt extinguishment	4.20%	5.40%
Other	3.40%	0.50%
Valuation allowance	13.40%	15.20%
Effective tax rate	0.00%	0.00%
Non-current deferred tax assets:
Net operating losses	$ 19,863	$ 15,966
Tax credits	241	241
Stock compensation	1,711	1,364
Other	156
Gross non-current deferred tax assets	21,971	17,571
Valuation allowance	(18,437)	(13,884)
Net non-current deferred tax assets	3,534	3,687
Non-current deferred tax liabilities:
Other		(21)
Property and equipment	(3,534)	(3,666)
Net non-current deferred tax liability	(3,534)	$ (3,687)
Increase in valuation allowance	$ 4,600,000