Summary of Financial Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Total before discount and debt issuance costs	$ 18,004	$ 13,736
Less: Current portion of notes payable	(2,000)
Less: Current portion of financial liabilities	(12,401)	(9,829)
Less: Current portion of unamortized discount and debt issuance costs	(557)	(404)
Less: Long-term portion of unamortized discount and debt issuance costs	(424)	(582)
Long-term financial liabilities	2,622	2,921
Term Loan
Debt Instrument [Line Items]
Total before discount and debt issuance costs	4,859	5,000
Notes Payable
Debt Instrument [Line Items]
Total before discount and debt issuance costs	2,000
Revolving Credit Facility
Debt Instrument [Line Items]
Total before discount and debt issuance costs	$ 11,145	$ 8,736