SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Allowance for doubtful accounts
Schedule of Valuation and Qualifying Accounts [Roll Forward]
Balance at Beginning of Year	$ 770	$ 582
Additions Charged to Costs and Expenses	82	543
Additions Charged to other Accounts	0	0
Deductions	(144)	(355)
Balance at End of Year	708	770
Allowance for obsolete inventories
Schedule of Valuation and Qualifying Accounts [Roll Forward]
Balance at Beginning of Year	524	566
Additions Charged to Costs and Expenses	986	710
Additions Charged to other Accounts	0	0
Deductions	(636)	(752)
Balance at End of Year	874	524
Valuation allowance for deferred tax assets
Schedule of Valuation and Qualifying Accounts [Roll Forward]
Balance at Beginning of Year	12,793	11,436
Additions Charged to Costs and Expenses	604	1,357
Additions Charged to other Accounts	0	0
Deductions	(1,022)	0
Balance at End of Year	12,375	12,793
Reserve for sales returns
Schedule of Valuation and Qualifying Accounts [Roll Forward]
Balance at Beginning of Year	76	117
Additions Charged to Costs and Expenses	1,068	1,188
Additions Charged to other Accounts	0	0
Deductions	(1,076)	(1,229)
Balance at End of Year	$ 68	$ 76