Income Taxes - Summary of Unrecognized Gross Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Unrecognized tax benefits at beginning of year	$ 2,065	$ 1,391	$ 255
Additions for tax positions in prior years	0	0	408
Additions for tax positions in the current year	764	674	728
Unrecognized tax benefits at end of year	$ 2,829	$ 2,065	$ 1,391