Loan Agreement and Prior Term Loan Agreement - Summary of Term Loan Agreement (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Less: current portion of loan agreement, net of $9 in unamortized debt issuance costs	$ (1,241)	$ (9,888)
Long-term portion of loan agreement, net of $36 in unamortized debt issuance costs	23,714	$ 22,339
Senior Secured Credit Facilities Credit Agreement [Member]
Debt Instrument [Line Items]
2019	1,250
2020	1,250
2021	1,875
2022	2,500
2023	18,125
Total principal on loan agreement	25,000
Unamortized debt issuance costs	(45)
Carrying amount of loan agreement	24,955
Less: current portion of loan agreement, net of $9 in unamortized debt issuance costs	(1,241)
Long-term portion of loan agreement, net of $36 in unamortized debt issuance costs	$ 23,714

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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