Annual report pursuant to Section 13 and 15(d)

Subsequent Events - Additional Information (Detail)

v3.19.1
Subsequent Events - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Millions
1 Months Ended
Feb. 08, 2019
Nov. 12, 2018
Feb. 11, 2019
Feb. 08, 2019
Jan. 30, 2019
First Stage Member [Member]          
Subsequent Event [Line Items]          
Business Acquisition, Percentage of Voting Interests Acquired   33.30%      
Second Stage [Member]          
Subsequent Event [Line Items]          
Business Combination, Contingent Consideration, Liability   $ 180.0      
SPMA [Member]          
Subsequent Event [Line Items]          
Business Combination, Consideration Transferred   $ 35.0      
SPMA [Member] | First Stage Member [Member]          
Subsequent Event [Line Items]          
Business Acquisition, Percentage of Voting Interests Acquired 33.30%     33.30%  
Business Combination, Consideration Transferred       $ 35.0  
SPMA [Member] | Second Stage [Member]          
Subsequent Event [Line Items]          
Business Combination, Step Acquisition, Equity Interest in Acquiree, Percentage   100.00%      
Subsequent Event [Member] | Alexion [Member]          
Subsequent Event [Line Items]          
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, Low         $ 150.0
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High         $ 200.0
Subsequent Event [Member] | Development Option and Stock Purchase Agreement [Member] | Caelum [Member]          
Subsequent Event [Line Items]          
Sale of Stock Percentage of Shares Transferred on Transaction         19.90%
Sale of Stock, Consideration Received on Transaction         $ 30.0
Subsequent Event [Member] | Development Option and Stock Purchase Agreement [Member] | Alexion [Member]          
Subsequent Event [Line Items]          
Contingent Earn Out Payments Commercial Milestone         $ 325.0
Subsequent Event [Member] | Development Option and Stock Purchase Agreement [Member] | Caelum security holders [Member]          
Subsequent Event [Line Items]          
Equity Method Investment, Ownership Percentage         40.00%
Subsequent Event [Member] | SPMA [Member]          
Subsequent Event [Line Items]          
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares 5,833,333        
Subsequent Event [Member] | FBIO [Member]          
Subsequent Event [Line Items]          
Business Combination, Consideration Transferred     $ 13.1    
Business Acquisition, Share Price     $ 3.25