Computation of Income Tax Expense (Benefit) from Continuing Operations Using Federal Income Tax Rate (Detail) (USD $)
In Thousands, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Reconciliation Of Income Taxes [Line Items]      
Income tax expense (benefit) at U.S. statutory rate $ 1,666 $ 922 $ (6,016)
State taxes, net of valuation allowance 22 17 40
Non-deductible stock compensation 602 571 589
Non-deductible goodwill impairment     3,534
Effect of rate change on deferred items     1,289
Valuation allowance 21,686 651 16,400
Effect of non-U.S. operations, net of valuation allowance 0 0 0
Research tax credits (547) (851) (242)
Other non-deductible expenses 848 445 972
Total income tax expense $ 24,277 $ 1,755 $ 16,566