Marketable Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Gross Amortized Cost	$ 7,032	$ 16,781
Total Unrealized Gains	2	0
Total Unrealized Losses	(3)	(11)
Fair Value	7,031	16,770
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Gross Amortized Cost	2,996
Total Unrealized Gains	2
Total Unrealized Losses	0
Fair Value	2,998
Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Gross Amortized Cost	4,036	6,781
Total Unrealized Gains	0	0
Total Unrealized Losses	(3)	(6)
Fair Value	$ 4,033	6,775
Certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Gross Amortized Cost		10,000
Total Unrealized Gains		0
Total Unrealized Losses		(5)
Fair Value		$ 9,995