Balance Sheet Information - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Allowance for doubtful accounts	$ 119		$ 119		$ 121
Consigned inventory with customers	700		700		800
Allowance for inventory losses	1,900		1,900		$ 1,800
Depreciation and amortization	$ 800	$ 700	$ 2,300	$ 2,100
Equipment [Member]
Property, Plant and Equipment [Line Items]
Period over which assets are depreciated			5 years
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Period over which assets are depreciated			7 years
Building [Member]
Property, Plant and Equipment [Line Items]
Period over which assets are depreciated			30 years
Minimum [Member]
Property, Plant and Equipment [Line Items]
Standard term of accounts receivable			30 days
Minimum [Member] | Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Period over which assets are depreciated			3 years
Maximum [Member]
Property, Plant and Equipment [Line Items]
Standard term of accounts receivable			90 days
Useful lives of the assets			1 year
Maximum [Member] | Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Period over which assets are depreciated			5 years