Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Equipment and Revenue Recognition (Details)

v3.19.1
Summary of Significant Accounting Policies - Equipment and Revenue Recognition (Details) - Equipment
12 Months Ended
Dec. 31, 2018
Minimum  
Equipment and leasehold improvements  
Useful lives of assets 3 years
Maximum  
Equipment and leasehold improvements  
Useful lives of assets 5 years