Schedule II - Valuation and Qualifying Accounts (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Allowance for doubtful accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 526,000	$ 76,000	$ 407,000	$ 49,000
Additions charged to Expense or Revenue	160,000	27,000	285,000	27,000
Deductions and write-offs	(8,000)	(59,000)	(14,000)	(32,000)
Balance at End of Period	678,000	44,000	678,000	44,000
Allowance for product returns
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	305,000	112,000	215,000	88,000
Additions charged to Expense or Revenue	412,000	281,000	613,000	471,000
Deductions and write-offs	(447,000)	(231,000)	(558,000)	(397,000)
Balance at End of Period	270,000	162,000	270,000	162,000
Allowance for obsolescence
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	323,000	184,000	322,000	159,000
Additions charged to Expense or Revenue	43,000	58,000	67,000	83,000
Deductions and write-offs	(14,000)	0	(37,000)	0
Balance at End of Period	$ 352,000	$ 242,000	$ 352,000	$ 242,000