The following table summarizes the amortized cost and estimated fair value of the Company's U.S. Treasury securities and U.S. government-sponsored enterprise securities, which are considered to be available-for-sale investments and were included in short-term investments and long-term investments on the consolidated balance sheets (in thousands):


	December 31, 2022
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Short-term investments:
U.S. Treasury securities	$	32,174	$	3	$	(34	)	$	32,143
U.S. government-sponsored enterprise securities		66,106		68		(85	)		66,089
Long-term investments:
U.S. Treasury securities		7,242		—		(4	)		7,238
U.S. government-sponsored enterprise securities		34,686		—		(43	)		34,643
	$	140,208	$	71	$	(166	)	$	140,113

Certain short-term debt securities with original maturities of less than 90 days are included in cash and cash equivalents on the consolidated balance sheet and are not included in the table above. As of December 31, 2022, all short-term investments had contractual maturities within one year and all long-term investments had contractual maturities between one to two years. The Company had no investments during the year ended December 31, 2021.