Nature of Operations and Summary of Significant Accounting Policies - Narrative (Details) ¥ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($) installment	Dec. 31, 2016 USD ($) installment	Dec. 31, 2015 USD ($)	Jun. 30, 2015 CNY (¥)
Property, Plant and Equipment [Line Items]
Restricted cash | $		$ 3,100,000
Loss on foreign exchange | $	$ (451,000)		$ (333,000)	$ (204,000)
Long-Term Incentive Plan, Payment Commencing in February of the Calendar Year Immediately Following the Conclusion of the Performance Period
Property, Plant and Equipment [Line Items]
Long-term incentive plan, percentage of award payable in cash		50.00%
Long-term incentive plan, number of installments | installment		35
Long-Term Incentive Plan, Payment Commencing in February 2021 and Ending in December 2023
Property, Plant and Equipment [Line Items]
Long-term incentive plan, percentage of award payable in cash			50.00%
Long-term incentive plan, number of installments | installment			35
Software and Software Development Costs [Member] | Minimum
Property, Plant and Equipment [Line Items]
Property, and equipment useful life		3 years
Software and Software Development Costs [Member] | Maximum
Property, Plant and Equipment [Line Items]
Property, and equipment useful life	5 years
Furniture and Fixtures | Minimum
Property, Plant and Equipment [Line Items]
Property, and equipment useful life		5 years
Furniture and Fixtures | Maximum
Property, Plant and Equipment [Line Items]
Property, and equipment useful life		7 years
China
Property, Plant and Equipment [Line Items]
Restricted cash | ¥					¥ 20