ASC 606 Adoption Impact and Revenue from Contracts with Customers - Schedule of Contract Balances (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Accounts receivable, net
Accounts receivable, net	$ 20,167	$ 19,151	$ 19,048
Deferred contract acquisition costs:
Current	8,083	7,059	0
Non-current	18,393	16,079	0
Total deferred contract acquisition costs	26,476	23,138
Contract assets and contract liabilities:
Contract assets (included in prepaid expenses and other current assets)	991	736	0
Contract liabilities (deferred revenue)	14,750	13,568	$ 13,975
Net contract assets (liabilities)	$ (13,759)	$ (12,832)

Contract With Customer, Asset (Liabilities), Net [Abstract]

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Contract with Customer, Asset (Liability), Net

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Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.

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Amount, after accumulated amortization and accumulated impairment loss, of asset recognized from cost incurred to obtain or fulfill contract with customer.

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Amount, after accumulated amortization and accumulated impairment loss, of asset recognized from cost incurred to obtain or fulfill contract with customer; classified as current.

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Amount, after accumulated amortization and accumulated impairment loss, of asset recognized from cost incurred to obtain or fulfill contract with customer; classified as noncurrent.

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Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time, classified as current.

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Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable, classified as current.

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