Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014 Customer Distributor	Dec. 31, 2013 Customer	Dec. 31, 2012 Customer
Revenue, Major Customer [Line Items]
Number of distributors	2
Gross deferred revenue	$ 1,769,000	$ 1,269,000
Gross deferred cost of revenue	808,000	516,000
Revenue recognized under multi-element	3.00%	3.00%	3.00%
Foreign currency losses, net	(196,000)	(94,000)	(46,000)
Maturity period of cash and cash equivalents	Less than three months
Available-for-sale securities, failed auction, value	3,000,000
Number of customers accounted for trade account receivable	2	2
Number of customers	1	2	1
Cost of advertising	$ 1,832,000	$ 1,884,000	$ 1,910,000
Product warranty period	2 years
Percentage likelihood of tax benefit settlement	50.00%
Recognition period of non performance based stock options	5 years
Sales Revenue, Net [Member] | Customer Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues	14.70%		10.10%
Sales Revenue, Net [Member] | Geographic Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues	60.50%	59.50%	51.10%
Sales Revenue, Net [Member] | Hong Kong [Member] | Geographic Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues	20.20%	16.20%	12.50%
Sales Revenue, Net [Member] | CHINA | Geographic Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues	12.00%	11.30%
Sales Revenue, Net [Member] | TAIWAN, PROVINCE OF CHINA | Geographic Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues			9.00%
Customer One [Member]
Revenue, Major Customer [Line Items]
Percentage of trade account receivable	14.90%	12.90%
Customer One [Member] | Sales Revenue, Net [Member] | Customer Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues		10.90%
Customer Two [Member]
Revenue, Major Customer [Line Items]
Percentage of trade account receivable	11.60%	12.50%
Customer Two [Member] | Sales Revenue, Net [Member] | Customer Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues		10.10%
Maximum [Member]
Revenue, Major Customer [Line Items]
Recognition period	12 months
Estimated useful life of intangible assets	20 years
Minimum [Member]
Revenue, Major Customer [Line Items]
Recognition period	6 months
Estimated useful life of intangible assets	3 years