Cash Equivalents and Marketable Securities - Schedule of Estimated Fair Value of Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule Of Available For Sale Securities [Line Items]
Cash equivalents, amortized cost	$ 21,250	$ 20,238
Cash equivalents, estimated fair value	21,250	20,238
Marketable securities, amortized cost	2,946	3,769
Marketable securities, gross unrealized gains	1
Marketable securities, gross unrealized losses		(1)
Marketable securities, estimated fair value	2,947	3,768
Money market funds
Schedule Of Available For Sale Securities [Line Items]
Cash equivalents, amortized cost		3,988
Cash equivalents, estimated fair value		3,988
Reverse repurchase agreements
Schedule Of Available For Sale Securities [Line Items]
Cash equivalents, amortized cost	21,250	16,250
Cash equivalents, estimated fair value	21,250	16,250
US government and agency securities
Schedule Of Available For Sale Securities [Line Items]
Marketable securities, amortized cost	2,946	3,769
Marketable securities, gross unrealized gains	1
Marketable securities, gross unrealized losses		(1)
Marketable securities, estimated fair value	$ 2,947	$ 3,768