Summary of Significant Accounting Policies - Summary of Useful Lives of Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2017
Research and Development Equipment
Property Plant And Equipment [Line Items]
Property plant and equipment useful life	5 years
Furniture and Office Equipment
Property Plant And Equipment [Line Items]
Property plant and equipment useful life	5 years
Computer Equipment
Property Plant And Equipment [Line Items]
Property plant and equipment useful life	3 years
Software | Minimum
Property Plant And Equipment [Line Items]
Property plant and equipment useful life	3 years
Software | Maximum
Property Plant And Equipment [Line Items]
Property plant and equipment useful life	5 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property plant and equipment useful life	Shorter of lease term or estimated useful life