Revenue Recognition - Accounts Receivable and Deferred Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Assets
Accounts receivable, net of allowance	$ 62,223	$ 44,089
Liabilities:
Deferred revenue, current portion	4,131	1,420
Deferred revenue, long-term portion	40,058
Total deferred revenues	44,189	1,420
Current accounts receivable	62,223	44,089
Other noncurrent assets	3,317	$ 3,979
Evercord
Liabilities:
Deferred revenue, current portion	2,100
Deferred revenue, long-term portion	2,900
Noncurrent accounts receivable	500
Evercord | Processing and storage services
Assets
Accounts receivable, net of allowance	$ 3,400
Liabilities:
Prepayment plan, delivery duration (in years)	18 years
Accounts receivable	$ 3,900
Current accounts receivable	3,400
Noncurrent accounts receivable	500
Other noncurrent assets	$ 500
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