Summary of Significant Accounting Policies - Summary of Estimated Lives of Assets (Detail)	12 Months Ended
	Dec. 31, 2019
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives	3 years
Furniture
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives	5 years
Minimum | Machine Manufacturing Equipment and Demonstration Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives	3 years
Minimum | Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives	3 years
Maximum | Machine Manufacturing Equipment and Demonstration Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives	5 years
Maximum | Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives	10 years