Quarterly report pursuant to Section 13 or 15(d)

Collaboration Agreement - Additional Information (Detail)

v3.3.0.814
Collaboration Agreement - Additional Information (Detail) - USD ($)
 1 Months Ended 3 Months Ended 4 Months Ended 9 Months Ended
Apr. 24, 2015
Dec. 31, 2009
Sep. 30, 2015
Sep. 30, 2014
Apr. 24, 2015
Sep. 30, 2015
Sep. 30, 2014
May. 14, 2015
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]                
Collaboration revenue     $ 6,737,000 $ 4,803,000   $ 12,136,000 $ 21,463,000  
Balance in advanced reimbursement payment recorded in deferred collaboration revenue     11,041,000     11,041,000    
Collaborative Arrangement | Teva Pharmaceutical Industries Ltd. [Member]                
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]                
Proceeds from advance reimbursement research and development $ 27,000,000              
Hold-back amount and third-party expenses deducted from termination payment 3,800,000       $ 3,800,000      
Hold-back amount deducted from termination payment 3,000,000       3,000,000      
Third-party expenses deducted from termination payment         $ 800,000      
Expected receivables from hold-back amount     3,000,000     3,000,000    
Maximum cost exposure if third-party agreements discovered after the termination date           100,000    
Collaboration revenue     6,700,000     12,100,000    
Balance in advanced reimbursement payment recorded in deferred collaboration revenue     11,000,000     $ 11,000,000    
Proceeds from advance reimbursement research and development, net amount   $ 50,000,000            
Collaborative Arrangement | Isis Pharmaceuticals Inc. and University of British Columbia [Member] | Minimum [Member]                
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]                
Percentage of net sales required to be paid as royalty to third party           4.00%    
Collaborative Arrangement | Isis Pharmaceuticals Inc. and University of British Columbia [Member] | Maximum [Member]                
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]                
Percentage of net sales required to be paid as royalty to third party           8.00%    
Collaborative Arrangement | Isis Pharmaceuticals Inc. [Member]                
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]                
Net proceed from collaboration agreement amount, requested payment percentage               30.00%
Proceeds from advance reimbursement research and development, net amount $ 23,200,000              
Hold-back amount, requested payment percentage               30.00%
Amount due to Isis for reimbursement for research and development activities     0     $ 0    
Milestone payment due           $ 20,000,000    
Period of milestone payment           21 days    
Reserve for contingency of non payment of non-royalty milestone amount     20,000,000     $ 20,000,000    
Milestone payment made     10,000,000     10,000,000    
Balance amount of milestone payment     $ 10,000,000     $ 10,000,000