Revenue Recognition - Additional Information (Details) - Accounting Standards Update 2014-09	3 Months Ended
	Mar. 31, 2018 USD ($)
Disaggregation Of Revenue [Line Items]
Unbilled receivables related to service	$ 700,000
Deferred sales commissions	12,500,000
Amortization expense for the deferred costs	1,200,000
impairment loss related to costs capitalized	0
Subscription services revenue recognized from unearned revenue	24,500,000
Revenue remaining performance obligation	$ 68,500,000
Description of revenue recognize on remaining performance obligation	The Company expects to recognize revenue on approximately $68.5 million of these remaining performance obligations over the next 12 months, with the balance recognized thereafter.
Remaining performance obligation recognition period	12 months
Subscription Services
Disaggregation Of Revenue [Line Items]
Revenue remaining performance obligation	$ 64,500,000