Income Taxes - Summary of Deferred tax assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating loss carryforwards	$ 446	$ 492
Deferred revenue	220	233
Stock based compensation	556	605
Accrual and reserves	529	209
Research and development credits, net of tax reserve	228	818
Other	14	18
Lease liability	77	98
Total gross deferred tax assets	2,070	2,473
Less valuation allowance		0
Net deferred tax assets	2,070	2,473
Deferred tax liabilities:
Depreciation and amortization	(49)	(12)
Right of use assets	(75)	(96)
Total deferred tax liabilities	(124)	(108)
Net deferred tax assets	$ 1,946	$ 2,365