Licensing Agreements - Additional Information (Detail) - USD ($)
3 Months Ended 12 Months Ended
Dec. 31, 2015
Sep. 30, 2015
Jun. 30, 2015
Mar. 31, 2015
Dec. 31, 2014
Sep. 30, 2014
Jun. 30, 2014
Mar. 31, 2014
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]                      
Research and development $ 7,157,000 $ 7,092,000 $ 6,678,000 $ 5,021,000 $ 4,701,000 $ 2,928,000 $ 2,648,000 $ 1,495,000 $ 25,948,000 $ 11,772,000 $ 9,700,000
Calando Pharmaceuticals, Inc. [Member]                      
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]                      
Bankruptcy proceedings, court where petition was filed                 District of Delaware    
Bankruptcy petition date filed                 Mar. 03, 2015    
Bankruptcy description                 In March 2014, Calando entered Chapter 7 bankruptcy in the District of Delaware and, as a result, the intellectual property rights the Company has obtained from Calando are subject to potential risks that may arise in connection with bankruptcy.    
Calando Product License Agreement [Member] | Upon achievement of specified regulatory and commercial milestones [Member]                      
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]                      
Milestone payment                 $ 32,800,000    
Calando Platform License Agreement [Member]                      
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]                      
Milestone payment                 17,800,000    
Calando Platform License Agreement [Member] | CRLX301 [Member]                      
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]                      
Milestone payment                 250,000    
SUNY License Agreement [Member]                      
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]                      
Research and development                 36,000 30,000 25,000
MIT License Agreement [Member]                      
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]                      
Research and development                 $ 50,000 $ 10,000 $ 10,000