Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Summary of Employee and Nonemployee Stock Option Activity (Detail)

v3.7.0.1
Stock-Based Compensation - Summary of Employee and Nonemployee Stock Option Activity (Detail) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 12 Months Ended
Mar. 31, 2017
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Shares granted (in shares) 468,000  
Options Outstanding, Number of Shares Outstanding    
Outstanding, beginning balance (in shares) 2,198,000  
Shares granted (in shares) 468,000  
Canceled or expired (in shares) (146,000)  
Outstanding, ending balance (in shares) 2,520,000  
Exercisable (in shares) 1,381,000  
Options Outstanding, Weighted-Average Exercise Price    
Outstanding, beginning balance (usd per share) $ 9.09  
Shares granted (usd per share) 2.49  
Cancelled or expired (usd per share) 9.49  
Outstanding, ending balance (usd per share) 7.84  
Exercisable (usd per share) $ 10.17  
Weighted-Average Remaining Contractual Term (in years)    
Outstanding 7 years 1 month 6 days 7 years 15 days
Exercisable 5 years 6 months 22 days  
Aggregate Intrinsic Value    
Outstanding, beginning balance $ 0  
Outstanding, ending balance 1,558  
Exercisable $ 161