Short-term Investments (Tables)

6 Months Ended

Jun. 30, 2019

Investments, Debt and Equity Securities [Abstract]

Summary of Amortized Cost, Gross Unrealized Gains and Losses, and Fair Value of Short-term Investments

The following table summarizes the amortized cost, gross unrealized gains and losses, and fair value of available-for-sale investments as of June 30, 2019:

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Aggregate Fair Value
U.S. government debt securities	$	67,256	$	45	$	—	$	67,301
Certificates of deposit	340		—		—		340
Total	$	67,596	$	45	$	—	$	67,641

The following table summarizes the amortized cost, gross unrealized gains and losses, and fair value of available-for-sale investments as of December 31, 2018:

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Aggregate Fair Value
U.S. government debt securities	$	119,401	$	—	$	(61	)	$	119,340
Certificates of deposit	348		—		—			348
Total	$	119,749	$	—	$	(61	)	$	119,688