Acquisitions (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended
	Oct. 31, 2018	Sep. 30, 2018	Jan. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Business Acquisition [Line Items]
Payments related to contingent consideration				$ 487	$ 0
AdvantageTec
Business Acquisition [Line Items]
Aggregate purchase price	$ 11,200
Cash payment in acquisition	6,000
Equity consideration in acquisition	4,300
Potential earn-out consideration payments based on achieving targets	900			400
Goodwill acquired in acquisition	9,100
Intangible assets acquired	$ 2,200
Conversable, Inc.
Business Acquisition [Line Items]
Aggregate purchase price		$ 5,700
Cash payment in acquisition		1,300
Equity consideration in acquisition		2,900
Potential earn-out consideration payments based on achieving targets		1,500
Goodwill acquired in acquisition		5,500
Intangible assets acquired		500
Assets acquired and liabilities assumed, net liability		$ (300)		$ 300
BotCentral
Business Acquisition [Line Items]
Equity consideration in acquisition			$ 1,000
Intangible assets acquired			1,200
Business acquisition transaction costs			$ 200