Annual report pursuant to Section 13 and 15(d)

Collaboration Agreement - Additional Information (Detail)

v3.3.1.900
Collaboration Agreement - Additional Information (Detail) - USD ($)
 1 Months Ended 3 Months Ended 4 Months Ended 12 Months Ended
Apr. 24, 2015
Dec. 31, 2009
Dec. 31, 2015
Sep. 30, 2015
Jun. 30, 2015
Mar. 31, 2015
Dec. 31, 2014
Sep. 30, 2014
Jun. 30, 2014
Mar. 31, 2014
Apr. 24, 2015
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
May. 14, 2015
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]                              
Collaboration revenue     $ 6,024,000 $ 6,737,000 $ 4,025,000 $ 1,374,000 $ 5,653,000 $ 4,803,000 $ 4,929,000 $ 11,731,000   $ 18,160,000 $ 27,116,000 $ 29,882,000  
Balance in advanced reimbursement payment recorded in deferred collaboration revenue     5,040,000                 5,040,000      
Collaborative Arrangement [Member] | 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 advanced reimbursement payment $ 3,800,000                   3,800,000        
Hold-back amount deducted from advanced reimbursement payment 3,000,000                   3,000,000        
Third-party expenses deducted from advanced reimbursement payment                     $ 800,000        
Maximum cost exposure if third-party agreements discovered after the termination date                       100,000      
Collaboration revenue                       18,200,000      
Proceeds from advance reimbursement research and development, net amount   $ 50,000,000                          
Collaborative Arrangement [Member] | Ionis Pharmaceuticals Inc. and University of British Columbia [Member]                              
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]                              
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      
Collaborative Arrangement [Member] | Ionis 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 [Member] | Ionis 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 [Member] | Ionis Pharmaceuticals Inc. [Member]                              
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]                              
Net proceed from collaboration agreement amount, requested payment percentage                             20.00%
Proceeds from advance reimbursement research and development, net amount $ 23,200,000                            
Hold-back amount, requested payment percentage                             30.00%
Amount due to Ionis 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      
Collaborative Arrangement [Member] | Ionis Pharmaceuticals Inc. [Member] | Maximum [Member]                              
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]                              
Damages arise due to termination of agreement                       $ 10,000,000