Summary Of Significant Accounting Policies - Additional Information (Detail) (USD $)	9 Months Ended	12 Months Ended				3 Months Ended		9 Months Ended						9 Months Ended
	Sep. 30, 2012 Segment Customer Location Entity	Dec. 31, 2011 Customer	Sep. 30, 2011	Sep. 30, 2012 US Treasury and Government	Dec. 31, 2011 US Treasury and Government	Sep. 30, 2012 Foreign Exchange	Sep. 30, 2011 Foreign Exchange	Sep. 30, 2012 Foreign Exchange	Sep. 30, 2011 Foreign Exchange	Sep. 30, 2012 Customer A	Dec. 31, 2011 Customer A	Sep. 30, 2012 Customer B	Dec. 31, 2011 Customer B	Sep. 30, 2012 Maximum	Sep. 30, 2012 Maximum Cash and Cash Equivalents	Sep. 30, 2012 Maximum Short-term Investments	Sep. 30, 2012 Minimum	Sep. 30, 2012 Minimum Short-term Investments
Significant Accounting Policies [Line Items]
Percentage of cash, cash equivalent and short-term investments invested in money market fund	92.00%	61.00%
Number of financial institution in which financial instruments invested	1
Number of major customers	2	2
Percentage of single significant customer balance to total Accounts Receivables										45.00%	33.00%	43.00%	34.00%
Short term investment maturity period															90 days	1 year		90 days
Available-for-sale investment amortized cost	$ 9,037,000	$ 26,029,000		$ 27,900,000	$ 34,900,000
Available-for-sale estimated fair value	9,043,000	26,036,000		27,900,000	34,900,000
Unrealized gain on available-for-sale investments	6,000	7,000		6,000	7,000
Estimated useful life of property plant and equipment														7 years			3 years
Percentage of prompt payment discount accrued at the time of sale	100.00%
Standard product warranty description	Although allowances and accruals are recorded at the time of product sale, certain rebates are typically paid out, on average, up to six months or longer after the sale. Reserve estimates are evaluated quarterly and if necessary, adjusted to reflect actual results.
Unrecognized tax benefits	0	0
Other income						10,000			15,000
Other expense							$ 32,000	$ 3,000
Stock options and warrants Purchase	11,379,953		11,682,969
Number of business segment	1
Number of geographic area within which the company operates predominantly	1