Income Taxes - Summary of Activity Related to Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Unrecognized benefit—beginning of period	$ 3,757	$ 3,261	$ 2,656
Gross increases—current period tax positions	455	496	605
Unrecognized benefit—end of period	$ 4,212	$ 3,757	$ 3,261