Credit Facility and Term Loans - Schedule of Credit Facility and Term Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Total Mid Cap credit facility	$ 13,640	$ 14,451	$ 3,631
Less: deferred debt issuance costs		(400)	(100)
Term loan-non current portion	13,339	13,049	4,732
Mid Cap Credit Facility
Debt Instrument [Line Items]
MidCap credit facility	15,114	16,455	4,575
Less: deferred debt issuance costs	(1,442)	(1,960)	(876)
Less discount associated with issuance of warrants	(32)	(44)
Total Mid Cap credit facility	13,640	14,451	3,631
Less discount associated with issuance of warrants		(44)	$ (68)
Horizon Term Loan
Debt Instrument [Line Items]
Horizon term loan	15,000	15,000
Less: deferred debt issuance costs	(906)	(1,022)
Less discount associated with issuance of warrants	(755)	(929)
Total Horizon term loan	13,339	13,049
Less-current portion	0	0
Term loan-non current portion	$ 13,339	$ 13,049

Current Portion Of Long Term Debt

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Discount associated with issuance of warrants.

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Discount associated with issuance of warrants current.

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- Definition

Lines of credit gross current.

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No definition available.

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- Definition

Loans payable gross.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Amount, after accumulated amortization, of debt issuance costs classified as current. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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The carrying value as of the balance sheet date of the current portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Including the current and noncurrent portions, aggregate carrying value as of the balance sheet date of loans payable (with maturities initially due after one year or beyond the operating cycle if longer).

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Carrying value as of the balance sheet date of loans payable (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion.

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