The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Intangible Assets And Goodwill - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Nov. 09, 2018	Sep. 10, 2018
Finite-Lived Intangible Assets [Line Items]
Amortization expense from finite-lived intangible assets	$ 1,000,000.0	$ 0	$ 2,300,000	$ 0
Carrying amount of goodwill	$ 47,453,000		$ 47,453,000		$ 47,453,000
Workpop Inc.
Finite-Lived Intangible Assets [Line Items]
Carrying amount of goodwill							$ 10,525,000
Workpop Inc. \| Developed technology
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired					7,500,000
Grovo Learning, Inc.
Finite-Lived Intangible Assets [Line Items]
Carrying amount of goodwill						$ 11,034,000
Grovo Learning, Inc. \| Developed technology
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired					$ 7,200,000