Annual report pursuant to Section 13 and 15(d)

Income Taxes - Additional Information (Detail)

v3.3.1.900
Income Taxes - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Income Taxes Disclosure [Line Items]      
Income tax (benefit) provision $ 0 $ (202,000) $ 202,000
NOL DTA related to excess benefits from stock option exercises 500,000    
Increase (decrease) in valuation allowance (6,200,000) 7,800,000 $ 11,600,000
Accrued interest or penalties 0 $ 0  
Federal [Member]      
Income Taxes Disclosure [Line Items]      
Federal and State net operating loss carryforwards $ 124,000,000    
Year net operating loss carryforwards begin to expire 2021    
Research and development credits $ 8,400,000    
Year research and development credits begin to expire 2022    
State [Member]      
Income Taxes Disclosure [Line Items]      
Federal and State net operating loss carryforwards $ 95,000,000    
Year net operating loss carryforwards begin to expire 2016    
Research and development credits $ 5,500,000