Cash Equivalents and Marketable Securities - Schedule of Estimated Fair Value of Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule Of Available For Sale Securities [Line Items]
Cash equivalents, amortized cost	$ 45,540	$ 20,238
Cash equivalents, estimated fair value	45,540	20,238
Marketable securities, amortized cost	18,488	3,769
Marketable securities, gross unrealized gains	4
Marketable securities, gross unrealized losses	(1)	(1)
Marketable securities, estimated fair value	18,491	3,768
Money market funds
Schedule Of Available For Sale Securities [Line Items]
Cash equivalents, amortized cost	5,290	3,988
Cash equivalents, estimated fair value	5,290	3,988
Reverse repurchase agreements
Schedule Of Available For Sale Securities [Line Items]
Cash equivalents, amortized cost	39,250	16,250
Cash equivalents, estimated fair value	39,250	16,250
US government and agency securities
Schedule Of Available For Sale Securities [Line Items]
Cash equivalents, amortized cost	1,000
Cash equivalents, estimated fair value	1,000
Marketable securities, amortized cost	18,488	3,769
Marketable securities, gross unrealized gains	4
Marketable securities, gross unrealized losses	(1)	(1)
Marketable securities, estimated fair value	$ 18,491	$ 3,768