Goodwill and Other Intangible Assets - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Line Items]
Goodwill		$ 8,759,000	$ 633,000
Amortization expense of intangible assets		2,200,000	1,300,000
Positive fair value of reporting unit		11,000,000
Stockholders' deficit balance		$ 6,856,000	2,864,000	$ (217,000)
Goodwill impairment loss	$ 0		$ 0
Portal | Minimum
Goodwill [Line Items]
Useful life of intangible assets		4 years
Portal | Maximum
Goodwill [Line Items]
Useful life of intangible assets		6 years
Customer relationships
Goodwill [Line Items]
Useful life of intangible assets		8 years