Organization and Summary of Significant Accounting Policies (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Changes in the inventory reserves [Roll Forward]
Balance at beginning of year	$ 3,925	$ 4,366	$ 4,829
Provision for inventory write-downs	615	34	93
Deduction for inventory write-offs	(831)	(475)	(556)
Balance at end of year	$ 3,709	$ 3,925	$ 4,366