Property and Equipment - Net - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 2,000,000	$ 1,900,000
Property and equipment gross	63,048,000		$ 62,353,000
Accumulated depreciation	45,360,000		$ 43,646,000
Capitalized software impairment	226,000
General and Administrative Expenses [Member]
Property, Plant and Equipment [Line Items]
Capitalized software impairment	200,000	0
Computer Equipment and Software Held Under Finance Leases [Member]
Property, Plant and Equipment [Line Items]
Property and equipment gross	8,400,000	8,000,000
Accumulated depreciation	5,300,000	3,000,000
Software Development for Internal Use [Member]
Property, Plant and Equipment [Line Items]
Capitalized software dovelopment costs	700,000	800,000
Software Development for Sale or License [Member]
Property, Plant and Equipment [Line Items]
Capitalized software dovelopment costs	300,000	800,000
Software Capitalized for Internal Use [Member] | Depreciation and Amortization [Member]
Property, Plant and Equipment [Line Items]
Amortization costs sale or license	$ 1,100,000	$ 1,100,000