Organization and Summary of Significant Accounting Policies - Additional Information (Detail) shares in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) Segment shares	Dec. 31, 2014 USD ($) shares	Dec. 31, 2013 USD ($) shares
Organization and Summary of Significant Accounting Policies [Line Items]
Maximum period for cash and highly liquid securities with original maturities	90 days or less
Minimum period for marketable securities classified as available-for-sale with original maturities	More than 90 days
Amount of letter of credit, description	The Company is required to maintain a letter of credit securing an amount equal to twelve months of the current monthly installment of base rent for the term of the lease for its facilities, which ends in August 2017.
Restricted cash	$ 3,246,000	$ 3,182,000
Weighted average amortization period for capitalized patent costs	9 years
Research and development expense	$ 230,000	350,000	$ 889,000
Accruals for potential disallowed costs on government contracts	$ 49,000	$ 49,000
Common stock equivalents excluded from the calculation of diluted net income per share | shares	0.3	0.5	0.9
Likelihood threshold for recognition of uncertain tax position	50.00%
Unrecognized tax benefits	$ 0
Number of business segment | Segment	1
Expected forfeiture rate of equity based compensation	8.75%	8.75%	11.20%
Patent application costs [Member]
Organization and Summary of Significant Accounting Policies [Line Items]
Estimated economic lives of the patents	20 years
Equipment [Member]
Organization and Summary of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment	10 years
Minimum [Member] | All other property and equipment [Member]
Organization and Summary of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment	3 years
Maximum [Member] | All other property and equipment [Member]
Organization and Summary of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment	5 years