Litigation, Commitments and Contingencies - Contingencies (Details) - Connected Data, Inc. $ in Millions		12 Months Ended
Oct. 14, 2015 USD ($) period payment	Dec. 31, 2017 USD ($) shares
Business Acquisition [Line Items]
Percentage of stock owned in acquired entity	100.00%
Purchase price	$ 6.7
Future contingent consideration	$ 5.0
Number of potential payments \| payment	3
Number of periods to achieve revenue targets \| period	3
Duration of target periods	6 months
Accrual for possible contingent compensation		$ 0.3
Estimate of Fair Value Measurement
Business Acquisition [Line Items]
Future contingent consideration	$ 0.8
Common Stock
Business Acquisition [Line Items]
Discount rate	15.00%
Possible contingent compensation payment, number of shares (in shares) \| shares		57,482

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Number of shares of equity interests issued or issuable to acquire entity.

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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.

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Amount of liability recognized arising from contingent consideration in a business combination, expected to be settled beyond one year or the normal operating cycle, if longer.

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Amount recognized for assets, including goodwill, in excess of (less than) the aggregate liabilities assumed.

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Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

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