Investments, Available-for-Sale (Tables)

12 Months Ended

Dec. 31, 2021

Investments, Debt and Equity Securities [Abstract]

Schedule of Cost, Gross Unrealized Holding Gains, Gross Unrealized Holding Losses and Fair Value of Available for Sale Investments

The Company's available-for-sale investments consisted of the following (in thousands):

December 31, 2021	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
Short-term
U.S. treasury securities	$	10,014	$	—	$	(1	)	$	10,013
Certificates of deposit		961		—		(1	)		960
Short-term investments, available-for-sale	$	10,975	$	—	$	(2	)	$	10,973
Long-term
U.S. treasury securities	$	42,517	$	—	$	(98	)	$	42,419
Certificates of deposit		970		—		(3	)		967
Investments, available-for-sale	$	43,487	$	—	$	(101	)	$	43,386
December 31, 2020
U.S. treasury securities	$	215,185	$	—	$	(31	)	$	215,154
Short-term investments, available-for-sale	$	215,185	$	—	$	(31	)	$	215,154