Investments (Tables)

6 Months Ended

Jun. 30, 2019

Investments

Summary of the Company's cash equivalents and investments

	June 30, 2019
			Gross		Gross		Estimated
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value
	(in thousands)
Cash equivalents:
Money market funds	$	218,783	$	—	$	—	$	218,783
U.S. treasury notes		26,567		—		—		26,567
Short-term investments:
Certificates of deposit		734		—		—		734
U.S. treasury notes		12,979		8		(11)		12,976
U.S. government agency securities		13,185		—		(13)		13,172
Total	$	272,248	$	8	$	(24)	$	272,232

	December 31, 2018
			Gross		Gross		Estimated
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value
	(in thousands)
Cash equivalents:
Money market funds	$	34,526	$	—	$	—	$	34,526
Short-term investments:
Certificates of deposit		3,873		—		(7)		3,866
U.S treasury notes		44,897		—		(142)		44,755
U.S. government agency securities		50,598		—		(169)		50,429
Long-term investments:
Certificates of deposit		244		—		(1)		243
Total	$	134,138	$	—	$	(319)	$	133,819