Revenue Recognition - Accounts Receivable and Deferred Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Dec. 31, 2018
Assets
Accounts receivable, net of allowance	$ 60,293	$ 62,223
Liabilities:
Deferred revenue, current portion	4,928	4,131
Deferred revenue, long-term portion	39,698	40,058
Total deferred revenues	44,626	44,189
Current accounts receivable	60,293	62,223
Other noncurrent assets	2,802	$ 3,317
Evercord
Liabilities:
Deferred revenue, long-term portion	$ 3,300
Evercord \| Processing and storage services \| Alternate
Liabilities:
Billing collection period (in months)	12 months
Evercord \| Processing and storage services \| Minimum
Liabilities:
Billing collection period (in months)	6 months
Evercord \| Processing and storage services \| Maximum
Liabilities:
Billing collection period (in months)	18 months
Evercord \| Storage services
Liabilities:
Deferred revenue, current portion	$ 1,200
Prepayment plan, delivery duration (in years)	18 years
Accounts receivable	$ 3,900
Other noncurrent assets	$ 200
Evercord \| Storage services \| Alternate
Liabilities:
Prepayment plan, financing duration (in months)	12 months
Evercord \| Storage services \| Minimum
Liabilities:
Prepayment plan, financing duration (in months)	6 months
Evercord \| Storage services \| Maximum
Liabilities:
Prepayment plan, financing duration (in months)	18 months

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Duration of services delivery under prepayment plan in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Includes, but not limited to, weeks in a year or quarter.

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For an unclassified balance sheet, the amount due from customers or clients for goods or services that have been delivered or sold in the normal course of business, reduced to their 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 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 of obligation to transfer good or service to customer for which consideration has been received or is receivable.

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