Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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- Definition

Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

+ References

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- Definition

Unrecognized cost of unvested options awarded to employees as compensation.

+ References

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Stock-Based Awards - Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Stock-based compensation expense
Stock-based compensation expense	$ 5,249	$ 3,304	$ 10,392	$ 6,457
Unrecognized stock-based compensation cost, options	45,446		45,446
Unrecognized compensation, RSUs	10,760		$ 10,760
Weighted average recognition period unrecognized stock-based compensation cost (in years)			2 years 10 months 17 days
Cost of revenue.
Stock-based compensation expense
Stock-based compensation expense	190		$ 366
Research and development expense.
Stock-based compensation expense
Stock-based compensation expense	1,756	1,304	3,483	2,521
Selling and Marketing Expense [Member]
Stock-based compensation expense
Stock-based compensation expense	1,020	400	1,927	780
General and administrative expense.
Stock-based compensation expense
Stock-based compensation expense	$ 2,283	$ 1,600	$ 4,616	$ 3,156
Options to Purchase Common Stock
Stock-based compensation expense
Weighted average recognition period unrecognized stock-based compensation cost (in years)			2 years 10 months 17 days
Restricted Stock Unit Awards
Stock-based compensation expense
Weighted average recognition period unrecognized stock-based compensation cost (in years)			3 years 3 months