Marketable Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Cash equivalents
Carrying Value	$ 62,194	$ 5,563
Short-term investments
Amortized Cost	77,093	81,291
Unrealized Gains	327	58
Unrealized Losses	(47)	(4)
Aggregate Fair Value	77,373	81,345
Long-term investments
Amortized Cost	1,278	1,278
Unrealized Gains	0	0
Unrealized Losses	(4)	0
Aggregate Fair Value	1,274	1,278
Total marketable securities, Amortized Cost	140,565	88,132
Total marketable securities, Unrealized Gains	327	58
Total marketable securities, Unrealized Losses	(51)	(4)
Total marketable securities, Aggregate Fair Value	140,841	88,186
Money market funds
Cash equivalents
Carrying Value	62,194	3,068
U.S. treasury securities
Short-term investments
Amortized Cost	52,025	67,051
Unrealized Gains	323	34
Unrealized Losses	0	(2)
Aggregate Fair Value	52,348	67,083
Corporate bonds
Short-term investments
Amortized Cost	11,816	9,075
Unrealized Gains	4	24
Unrealized Losses	(47)	(2)
Aggregate Fair Value	11,773	9,097
Long-term investments
Amortized Cost	1,278	1,278
Unrealized Gains	0	0
Unrealized Losses	(4)	0
Aggregate Fair Value	1,274	1,278
Commercial paper
Cash equivalents
Carrying Value		2,495
Short-term investments
Amortized Cost	13,252	5,165
Unrealized Gains	0	0
Unrealized Losses	0	0
Aggregate Fair Value	$ 13,252	$ 5,165