Acquisition - Intangible assets acquired (Details) - USD ($) $ in Thousands		12 Months Ended
	Oct. 06, 2017	Dec. 31, 2018
Triage Business
Business Acquisition [Line Items]
Intangible Asset	$ 184,900
Purchased technology
Business Acquisition [Line Items]
Weighted-average useful life (years)		9 years 1 month
Purchased technology | Triage Business
Business Acquisition [Line Items]
Intangible Asset	$ 52,400
Weighted-average useful life (years)	10 years
Customer relationships
Business Acquisition [Line Items]
Weighted-average useful life (years)		7 years 10 days
Customer relationships | Triage Business
Business Acquisition [Line Items]
Intangible Asset	$ 115,000
Weighted-average useful life (years)	7 years
Trademarks | Triage Business
Business Acquisition [Line Items]
Intangible Asset	$ 17,500
Weighted-average useful life (years)	10 years