Supplementary Balance Sheet Information - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Accounts Receivable [Abstract]
Allowances for doubtful accounts	$ 1,200,000	$ 1,800,000
Provision for sales returns	210,000	210,000
Provision for excess and obsolete inventory	1,700,000	2,100,000
Deferred revenue recognized	18,000	119,000
Litigation Settlement Receivable	1,400,000
Legal settlement at present value	1,200,000
Litigation Expense Recovered		731,000
Settlement Expense For Dismissal of Patent Infringement Lawsuit Recovered	68,000
Deferred royalty revenue recognized	119,000	119,000
Deferred Royalties	142,000	261,000
Settled Litigation
Accounts Receivable [Abstract]
Deferred royalty revenue, net	$ 379,000
Licensing Agreements United States
Accounts Receivable [Abstract]
License period	3 years
Licensing Agreements Outside of United States
Accounts Receivable [Abstract]
License period	5 years
Assets Held Under Capital Lease
Accounts Receivable [Abstract]
Capital leased assets, Gross	$ 378,000	590,000
Accumulated depreciation related to assets held under capital lease	$ 227,000	$ 118,000