Commitments and Contingencies - Right of use assets and lease liabilities for operating leases (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Assets:
Right-of-use assets, net	$ 703	$ 842
Total lease assets	703	842
Current liabilities:
Operating lease liabilities, current	551	639
Non-current liabilities:
Operating lease liabilities, net of current portion	252	326
Total lease liability	$ 803	$ 965