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Organization and Description of Business - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2018 USD ($) Segment	Apr. 17, 2018 USD ($)	Dec. 31, 2017 USD ($)
Schedule of Capitalization, Equity [Line Items]
Number of reportable segments \| Segment	2
Accumulated deficit	$ 274,058,000		$ 268,022,000
Cash and cash equivalents	18,695,000		16,895,000
Debt outstanding under debt and capital lease obligations	10,200,000
Current debt	$ 461,000		$ 15,721,000
Subsequent Event [Member] \| New Credit Agreement [Member]
Schedule of Capitalization, Equity [Line Items]
Aggregate principal amount		$ 15,000,000
Subsequent Event [Member] \| New Credit Agreement [Member] \| Tranche B Term Loan [Member]
Schedule of Capitalization, Equity [Line Items]
Aggregate principal amount		$ 10,000,000