Organization and Summary of Significant Accounting Policies - Sales Return, Waranty, and Other Credits Liability (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019	Jan. 01, 2018	Jan. 01, 2017	Jan. 01, 2016
Sales Return and Warranty Liability [Roll Forward]
Balance at beginning of year	$ 54,432	$ 34,536	$ 30,720
Cumulative effect of accounting change	0			$ (39)	$ (3,880)	$ 5,250	$ 0
Additions charged to sales	128,642	149,930	90,018
Sales returns and warranty claims charged against reserve	(141,895)	(135,963)	(86,299)
Foreign currency translation loss	(54)	(167)	97
Balance at end of year	43,853	54,432	34,536
Gear4
Sales Return and Warranty Liability [Roll Forward]
Assumed in acquisition	0	846	0
HALO
Sales Return and Warranty Liability [Roll Forward]
Assumed in acquisition	$ 2,728	$ 0	$ 0