Quarterly report pursuant to Section 13 or 15(d)

Commitments and Contingencies - Additional Information (Detail)

Commitments and Contingencies - Additional Information (Detail)
3 Months Ended
Nov. 19, 2018
USD ($)
Dec. 11, 2017
Mar. 31, 2019
USD ($)
Mar. 31, 2018
USD ($)
Mar. 01, 2018
USD ($)
Other Commitments [Line Items]          
Consolidated lease rent and facilities expense     $ 100,000 $ 100,000  
Indemnification obligations     0    
Expenses related to indemnification issues     $ 0    
Vancouver Lease Arrangements [Member]          
Other Commitments [Line Items]          
Expiration of operating lease agreement     2019-01    
Vancouver Lease Arrangements [Member] | Vancouver, British Columbia [Member]          
Other Commitments [Line Items]          
Lease agreement commencement date Feb. 01, 2019        
Area of office space leased | ft² 2,367        
Initial term of lease expiration date Jan. 31, 2023        
Operating lease, term of contract 4 years        
Operating lease, option to extend, description     The initial term of the lease will expire on January 31, 2023, with an option to extend the term for one further four-year period    
Lessee, Operating Lease, Existence of Option to Extend [true false]     true    
Operating lease, initial monthly base rent expenses $ 5,200,000        
Operating lease, revised monthly base rent expenses 5,400,000        
Construction allowance 14,200,000        
Security deposit $ 18,600,000        
Seattle Lease Arrangement [Member] | Pike [Member]          
Other Commitments [Line Items]          
Area of office space leased | ft²   3,187      
Lease agreement     On December 11, 2017, we entered into a lease, or the Seattle Lease, with 520 Pike Street, Inc., or Pike, pursuant to which we leased approximately 3,187 square feet located at Suite 2250 at 520 Pike Tower, Seattle, Washington, 98101, which commenced on March 1, 2018. The initial term of the Seattle Lease will expire at the end of the month on the third anniversary of the Seattle Lease.    
Monthly base rent         $ 11,685,000
Monthly base rent, maximum annual increase         12,397,000
Lease, security deposit, annual payment         37,192,000
Lease, security deposit payment, annual decrease         $ 12,397,000
Percentage of profit attributable to lessor     50.00%    
Percentage of property if subleased could result in lease termination     50.00%