Annual report pursuant to Section 13 and 15(d)

Income Tax - Additional Information (Detail)

v3.3.1.900
Income Tax - Additional Information (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Income Taxes [Line Items]      
Income tax rate assumed for both State and Foreign deferred tax calculations 34.00% 34.00% 34.00%
Future enacted income tax rate assumed for both State and Foreign deferred tax calculations 34.00% 34.00% 34.00%
Net operating loss carryforwards $ 151,910 $ 151,100  
Unclaimed tax deductions $ 14,300    
Starting range of research and development tax credits expiration period 2016    
Ending range of research and development tax credits expiration period 2035    
Deferred tax assets recognized $ 0 0  
Unrecognized tax benefits 2,100    
Accrued interest and penalties related to income taxes 0 0  
Investment tax credits carryforwards [Member]      
Income Taxes [Line Items]      
Investment tax credits 4,561    
Research [Member]      
Income Taxes [Line Items]      
Investment tax credits 2,300    
CANADA | Investment tax credits carryforwards [Member]      
Income Taxes [Line Items]      
Investment tax credits 2,300 2,400  
CANADA | Non Capital Loss Carryforwards [Member]      
Income Taxes [Line Items]      
Investment tax credits $ 100,400 $ 96,300  
Canada [Member]      
Income Taxes [Line Items]      
Income tax rate assumed for both State and Foreign deferred tax calculations 26.00% 26.00% 25.75%
Future enacted income tax rate assumed for both State and Foreign deferred tax calculations 26.00% 26.00% 25.00%