Quarterly report pursuant to Section 13 or 15(d)

Intangibles - Additional Information (Detail)

v3.10.0.1
Intangibles - Additional Information (Detail) - USD ($)
3 Months Ended 6 Months Ended
Aug. 01, 2017
May 18, 2015
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 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        
License agreement amortization expense     $ 100,000 $ 100,000 $ 100,000 $ 100,000
Impairment of intangible assets         0  
Apatorsen License Agreements [Member]            
Finite Lived Intangible Assets [Line Items]            
Loss on disposition [note 4]         8,600,000  
Recovery of deferred income taxes [note 5]         $ 2,900,000