Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018 USD ($) Customer	Dec. 31, 2017 USD ($) Customer	Jan. 01, 2019 USD ($)	Jan. 01, 2018 USD ($)
Accounting Policies [Line Items]
Concentration Risk, Customer	No customer accounted for 10% or more of net revenue for the years ended December 31, 2018 and 2017, respectively. No customer accounted for 10% or more of the Company’s accounts receivable balance at December 31, 2018 or 2017.
Number of major customer represented stated percentage of total net revenue | Customer	0	0
Number of customers who accounted for 10% or more accounts receivable balance | Customer	0	0
Impairment losses on long lived assets	$ 0	$ 0
Capitalized software development costs, net	381,000
Software development costs capitalized in period		401,000
Amortization expense	2,085,000	1,455,000
Foreign currency translation and transactions gains (losses)	200,000	(400,000)
Accumulated deficit	(404,353,000)	(399,647,000)
Deferred Revenue	$ 2,174,000	900,000
Topic 606
Accounting Policies [Line Items]
Accumulated deficit				$ (399,645,000)
Capitalized incremental sales commission costs or other costs				0
Topic 606 | On Delivery
Accounting Policies [Line Items]
Percentage of revenue recognized	94.00%
Topic 606 | Over Time
Accounting Policies [Line Items]
Percentage of revenue recognized	6.00%
Topic 606 | Adjustments
Accounting Policies [Line Items]
Accumulated deficit				2,000
Deferred Revenue				$ (2,000)
Automobiles
Accounting Policies [Line Items]
Property and equipment, estimated useful lives	5 years
Purchased Software
Accounting Policies [Line Items]
Property and equipment, estimated useful lives	3 years
Research and Development
Accounting Policies [Line Items]
Estimated useful lives of intangible asset	3 years
Amortization expense	$ 200,000	$ 200,000
Minimum
Accounting Policies [Line Items]
Estimated useful lives of intangible asset	4 years
Minimum | Accounting Standards Update 2016-02 | Subsequent Event
Accounting Policies [Line Items]
Operating lease, right-of-use asset			$ 5,000,000
Operating lease, liability			5,000,000
Minimum | Furniture, Fixtures and Office Equipment
Accounting Policies [Line Items]
Property and equipment, estimated useful lives	3 years
Minimum | Plant and Machinery
Accounting Policies [Line Items]
Property and equipment, estimated useful lives	5 years
Maximum
Accounting Policies [Line Items]
Estimated useful lives of intangible asset	12 years
Maximum | Accounting Standards Update 2016-02 | Subsequent Event
Accounting Policies [Line Items]
Operating lease, right-of-use asset			6,000,000
Operating lease, liability			$ 6,000,000
Maximum | Furniture, Fixtures and Office Equipment
Accounting Policies [Line Items]
Property and equipment, estimated useful lives	10 years
Maximum | Plant and Machinery
Accounting Policies [Line Items]
Property and equipment, estimated useful lives	7 years