Basis of Presentation - Supplementary cash flows information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Non-cash information:
Right-of-use asset and lease liability recognized	$ 45	$ 3,140
Additions to property and equipment included in accounts payable	85	340
Restricted stock held for employee tax remittance included in accounts payable	(57)	0
Interest paid	$ 3	$ 5