Annual report pursuant to Section 13 and 15(d)

Income Tax - Summary of Investment Tax Credits and Non-Capital Losses and Net Operating Losses (Detail)

v3.19.1
Income Tax - Summary of Investment Tax Credits and Non-Capital Losses and Net Operating Losses (Detail) - USD ($)
$ in Thousands
Dec. 31, 2018
Dec. 31, 2017
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses $ 17,600 $ 9,900
Canada    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Non-capital Losses 123,295  
UK    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses 1,829 800
US [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses 17,598  
Investment tax credits carryforwards [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Investment Tax Credits 2,655  
Investment tax credits carryforwards [Member] | Canada    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Investment Tax Credits 2,600 $ 2,600
2026 [Member] | Canada    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Non-capital Losses 7,364  
2026 [Member] | Investment tax credits carryforwards [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Investment Tax Credits 244  
2027 [Member] | Canada    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Non-capital Losses 4,949  
2027 [Member] | Investment tax credits carryforwards [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Investment Tax Credits 71  
2028 [Member] | Canada    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Non-capital Losses 8,020  
2028 [Member] | Investment tax credits carryforwards [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Investment Tax Credits 148  
2029 [Member] | Canada    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Non-capital Losses (9)  
2029 [Member] | UK    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses 33  
2029 [Member] | US [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses 9  
2029 [Member] | Investment tax credits carryforwards [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Investment Tax Credits 317  
2030 [Member] | Canada    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Non-capital Losses 6,288  
2030 [Member] | UK    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses 20  
2030 [Member] | US [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses 5  
2030 [Member] | Investment tax credits carryforwards [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Investment Tax Credits 346  
2031 [Member] | Canada    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Non-capital Losses 12,121  
2031 [Member] | UK    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses 34  
2031 [Member] | US [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses 17  
2031 [Member] | Investment tax credits carryforwards [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Investment Tax Credits 486  
2032 [Member] | Canada    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Non-capital Losses 17,278  
2032 [Member] | UK    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses 41  
2032 [Member] | US [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses 43  
2032 [Member] | Investment tax credits carryforwards [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Investment Tax Credits 363  
2033 [Member] | Canada    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Non-capital Losses 23,240  
2033 [Member] | UK    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses 53  
2033 [Member] | US [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses 2  
2033 [Member] | Investment tax credits carryforwards [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Investment Tax Credits 193  
2034 [Member] | Canada    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Non-capital Losses 17,077  
2034 [Member] | UK    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses 45  
2034 [Member] | US [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses 3  
2034 [Member] | Investment tax credits carryforwards [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Investment Tax Credits 215  
2035 [Member] | Canada    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Non-capital Losses 3,112  
2035 [Member] | UK    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses 27  
2035 [Member] | US [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses 654  
2035 [Member] | Investment tax credits carryforwards [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Investment Tax Credits 122  
2036 [Member] | Canada    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Non-capital Losses 16,664  
2036 [Member] | UK    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses 56  
2036 [Member] | US [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses 611  
2036 [Member] | Investment tax credits carryforwards [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Investment Tax Credits 79  
2037 [Member] | Canada    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Non-capital Losses 4,254  
2037 [Member] | UK    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses 633  
2037 [Member] | US [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses 8,763  
2037 [Member] | Investment tax credits carryforwards [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Investment Tax Credits 19  
2038 [Member] | Canada    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Non-capital Losses 2,937  
2038 [Member] | UK    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses 887  
2038 [Member] | US [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Net Operating Losses 7,491  
2038 [Member] | Investment tax credits carryforwards [Member]    
Schedule Of Tax Credits And Losses Carry Forward Expiration [Line Items]    
Investment Tax Credits $ 52