Income Taxes - Schedule of Unrecognized Tax Benefits Roll Forward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Abstract]
Balance, beginning of the period	$ 4,880	$ 4,827	$ 5,236
Gross increases—tax positions in prior period	496	171	118
Gross decreases—tax positions in prior period	(61)	(362)	(735)
Gross increases—current-period tax positions	213	244	208
Lapse of statute of limitations	0	0	0
Balance, end of the period	$ 5,528	$ 4,880	$ 4,827