Revenue Recognition - Summary of Consideration Allocated to Performance Obligations (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Deferred revenue, current	$ 1,855	$ 1,705
Deferred revenue, net of current portion	853	802
Unsatisfied Training Obligations
Disaggregation of Revenue [Line Items]
Deferred revenue, current	93	67
Unsatisfied Contract-term Services
Disaggregation of Revenue [Line Items]
Deferred revenue, current	973	849
Deferred revenue, net of current portion	572	544
Total Deferred Revenue	1,545	1,393
Unsatisfied Pellet Procedures
Disaggregation of Revenue [Line Items]
Deferred revenue, current	789	789
Deferred revenue, net of current portion	281	258
Total Deferred Revenue	$ 1,070	$ 1,047