Cash, Cash Equivalents and Investments - Contractual Maturities (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Cash and Cash Equivalents [Abstract]
Due within one year or less	$ 16,961	$ 9,095
Due after one year through five years	32,189	11,861
Total	$ 49,150	$ 20,956