Organization and Summary of Significant Accounting Policies - Allowance For Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allowance for Doubtful Accounts [Roll Forward]
Balance at beginning of year	$ 824	$ 568	$ 1,910
Additions charged to expense	339	599	243
Assumed in acquisition of mophie	0	91	0
Write-offs charged against the allowance	(444)	(430)	(1,585)
Foreign currency translation gain (loss)	15	(4)	0
Balance at end of year	$ 734	$ 824	$ 568