Accrued Liabilities and Other Long-Term Liabilities - Summary of Other Long-Term Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Accrued Liabilities and Other Liabilities [Abstract]
Deferred rent	$ 561	$ 581
Leasehold incentive obligation	243	283
Other liabilities — deposits	0	2
Total other long-term liabilities	$ 804	$ 866	[1]

[1] The condensed balance sheet as of December 31, 2020 has been derived from the audited financial statements as of that date.