Valuation and Qualifying Accounts (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Allowance for doubtful accounts receivable [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning Balance	$ 49	$ 37	$ 9
Valuation and Qualifying Accounts, Additions	100	75	29
Valuation and Qualifying Accounts, Deductions	55	63	1
Ending Balance	94	49	37
Reserve for sales returns and allowances [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning Balance	105	40	53
Valuation and Qualifying Accounts, Additions		262	52
Valuation and Qualifying Accounts, Deductions		197	65
Ending Balance	105	105	40
Allowance for inventory valuation [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning Balance	267	206	32
Valuation and Qualifying Accounts, Additions	921	381	311
Valuation and Qualifying Accounts, Deductions	406	320	137
Ending Balance	782	267	206
Valuation allowance for deferred tax assets [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning Balance	31,685	29,316	27,312
Valuation and Qualifying Accounts, Additions	22,526	2,369	2,004
Valuation and Qualifying Accounts, Deductions
Ending Balance	$ 54,211	$ 31,685	$ 29,316