Investments and Fair Value Measurements - Recurring Basis (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2021	Dec. 31, 2020
Assets, Fair Value Disclosure [Abstract]
Investments, amortized cost	$ 12,361	$ 12,361	$ 5,966
Fair Value, Transfers Between Level 1 and Level 2, Description and Policy [Abstract]
Transfer from Level 1 to Level 2 , assets	0	0
Transfer from Level 2 to Level 1 , assets	0	0
Transfers into Level 3, assets	0	0
Transfer out of Level 3, assets	0	0
Recurring
Assets, Fair Value Disclosure [Abstract]
Total	12,361	12,361	5,966
Recurring | Certificates of deposit.
Assets, Fair Value Disclosure [Abstract]
Cash and cash equivalents, fair value disclosure	4,762	4,762	2,885
Recurring | Corporate bonds
Assets, Fair Value Disclosure [Abstract]
Investments, amortized cost	7,599	7,599	3,081
Recurring | Significant Other Observable Inputs (Level 2)
Assets, Fair Value Disclosure [Abstract]
Total	12,361	12,361	5,966
Recurring | Significant Other Observable Inputs (Level 2) | Certificates of deposit.
Assets, Fair Value Disclosure [Abstract]
Cash and cash equivalents, fair value disclosure	4,762	4,762	2,885
Recurring | Significant Other Observable Inputs (Level 2) | Corporate bonds
Assets, Fair Value Disclosure [Abstract]
Investments, amortized cost	$ 7,599	$ 7,599	$ 3,081