Short-term Investments

6 Months Ended

Jun. 30, 2023

Short Term Investments [Abstract]

Short-term Investments

5. Short-term Investments

The following is a summary of our short-term investments (in thousands):

	June 30, 2023
			Gross		Gross
	Amortized		Unrealized		Unrealized			Estimated
	Cost		Gains		Losses			Fair Value
U.S. treasury bills and government agency obligations	$	16,329	$	—	$	(6	)	$	16,323
Foreign commercial paper		3,459		—		—			3,459
Total	$	19,788	$	—	$	(6	)	$	19,782

	December 31, 2022
			Gross		Gross
	Amortized		Unrealized		Unrealized			Estimated
	Cost		Gains		Losses			Fair Value
U.S. treasury bills and government agency obligations	$	35,734	$	—	$	(19	)	$	35,715
U.S. commercial paper		5,481		—		—			5,481
Foreign commercial paper		28,292		—		—			28,292
Total	$	69,507	$	—	$	(19	)	$	69,488

The amortized cost of debt securities is adjusted for amortization of premiums and accretion of discounts to maturity. We regularly monitor and evaluate the realizable value of our marketable securities. We did not recognize any impairment losses during the three and six months ended June 30, 2023 and 2022.

Unrealized gains and losses associated with our investments are reported in accumulated other comprehensive income (loss). Realized gains and losses associated with our investments, if any, are reported in the statements of operations and comprehensive loss. We recognized $1,000 in realized losses during the three and six months ended June 30, 2023. We did not recognize any realized gains or losses during the three and six months ended June 30, 2022.