Allowance for Sales Returns - Summary of Allowance for Sales Returns (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance, beginning of period	$ 13,829	$ 9,806
Balance, end of period	12,783	13,829	$ 9,806
Allowance for sales returns
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance, beginning of period	6,268	4,155	6,266
Reserve accrual	12,819	17,108	13,042
Recoveries and deductions, net	(14,496)	(14,995)	(15,153)
Balance, end of period	$ 4,591	$ 6,268	$ 4,155