Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Marketable Securities [Line Items]
Gross Amortized Cost		$ 50,960
Total Unrealized Gains		0
Total Unrealized Losses		(28)
Fair Value	$ 0	50,932
Commercial paper
Marketable Securities [Line Items]
Gross Amortized Cost		22,886
Total Unrealized Gains		0
Total Unrealized Losses		(14)
Fair Value		22,872
Corporate bonds
Marketable Securities [Line Items]
Gross Amortized Cost		28,074
Total Unrealized Gains		0
Total Unrealized Losses		(14)
Fair Value		$ 28,060