Annual report pursuant to Section 13 and 15(d)

Intangibles - Additional Information (Detail)

v3.19.1
Intangibles - Additional Information (Detail) - USD ($)
1 Months Ended 12 Months Ended
Aug. 01, 2017
May 18, 2015
Aug. 31, 2017
Dec. 31, 2018
Dec. 31, 2017
Finite Lived Intangible Assets [Line Items]          
Intangible assets, Fair Value $ 8,600,000 $ 3,100,000      
Intangible assets, Useful life 6 years 14 years      
Loss on disposition [note 5]         $ 8,610,000
License agreement amortization expense       $ 200,000 $ 200,000
Impairment of intangible assets       $ 0  
Apatorsen License Agreements [Member]          
Finite Lived Intangible Assets [Line Items]          
Loss on disposition [note 5]     $ 8,600,000    
Recovery of deferred income taxes [note 5]     $ 2,900,000