Capped exit fee percentage on term loan principal amount.

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Debt instrument final payment fee.

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Line of credit facility final payment fees percentage.

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Line of credit facility increase in final payment fees percentage upon extension interest only periods.

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Line of credit facility interest-only period.

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Line of credit facility interest only period extension upon achievement of revenues.

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Line of credit facility prepayment fees percentage.

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- Definition

The floor interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding, including current maturities, which accrues interest at a rate subject to change from time to time.

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Number of default events.

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Percentage of exit fee for liquidation dissolution winding up or change of control.

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Percentage of exit fee upon achievement of any trailing twelve month revenues.

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Percentage of exit fee upon achievement of both trailing twelve month revenues.

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Term loans number of tranches.

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Trailing twelve month net product revenue first threshold limit to pay exit fee.

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Trailing twelve month net product revenue second threshold limit to pay exit fee.

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- Definition

Amount of amortization expense attributable to debt issuance costs.

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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No definition available.

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The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

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No definition available.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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- Definition

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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No definition available.

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Amount of unamortized debt discount (premium) and debt issuance costs.

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- Definition

Aggregate amount of interest expense on all borrowings.

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Amount of the cost of borrowed funds accounted for as interest expense for debt.

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The carrying value as of the balance sheet date of the current and noncurrent portions 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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Description of the credit facility's borrowing capacity including discussion of how the borrowing capacity is determined (for example, borrowing capacity based on the amount of current assets).

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Description of the conditions for borrowing under the credit facility including the nature of any restrictions.

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Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

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Date the credit facility terminates, in CCYY-MM-DD format.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Debt - Additional Information (Details)			3 Months Ended		9 Months Ended
Debt - Additional Information (Details)	Mar. 02, 2020 USD ($) Tranche Event	Feb. 29, 2020 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Mar. 31, 2017 USD ($)
Debt Instrument [Line Items]
Interest expense			$ 1,000,000.0	$ 900,000	$ 3,500,000	$ 2,800,000
Cash interest expense			800,000	700,000	3,100,000	2,200,000
Non-cash interest expense			200,000	$ 200,000	$ 400,000	$ 600,000
Solar Capital Ltd \| Term A Loan and Term B Loan
Debt Instrument [Line Items]
Basis spread on variable rate	1.66%
Interest rate	7.65%
Interest-only period	2022-03
Interest-only period upon achievement of revenues	2023-02
Number of default events \| Event	0
Line of credit facility, conversion to term loan, conditions					At the Company’s election, the interest only period may be extended through February 2023 if the Company satisfies a minimum net product revenue covenant through March 1, 2022 and no event of default shall have occurred
Solar Capital Ltd \| $35.0 Million Credit Facility
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity							$ 35,000,000.0
Solar Capital Ltd \| $35.0 Million Credit Facility \| Term A Loan
Debt Instrument [Line Items]
Borrowings outstanding under credit facility	$ 35,000,000.0
Solar Capital Ltd \| $50.0 Million Credit Facility
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 50,000,000.0
Term loans number of tranches \| Tranche	2
Increase in final payment fees percentage upon extension interest only periods	5.50%
Trailing twelve month net product revenue first threshold limit to pay exit fee	$ 100,000,000
Trailing twelve month net product revenue Second threshold limit to pay exit fee	$ 125,000,000
Percentage of exit fee for liquidation, dissolution, winding up or change of control of the Company	4.50%
Percentage of exit fee upon achievement of any trailing twelve month revenues	2.25%
Percentage of exit fee upon achievement of both trailing twelve month revenues	4.50%
Capped exit fee percentage on term loan principal amount	4.50%
Solar Capital Ltd \| $50.0 Million Credit Facility \| Prepaid on or Before First Anniversary of Funding
Debt Instrument [Line Items]
Prepayment fees percentage	3.00%
Solar Capital Ltd \| $50.0 Million Credit Facility \| Prepaid After First and on or Before Second Anniversary of Funding
Debt Instrument [Line Items]
Prepayment fees percentage	2.00%
Solar Capital Ltd \| $50.0 Million Credit Facility \| Prepaid After Second Anniversary of Funding
Debt Instrument [Line Items]
Prepayment fees percentage	1.00%
Solar Capital Ltd \| $50.0 Million Credit Facility \| Term A Loan
Debt Instrument [Line Items]
Credit facility maturity date	Feb. 28, 2025
Solar Capital Ltd \| $15 Million Credit Facility \| Term B Loan
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 15,000,000.0
Line of credit facility, conversion to term loan, conditions					Under the Term B Loan portion of the Solar Facility, the Company is permitted to borrow, at its election, up to an aggregate amount of $15.0 million, (i) upon the Company achieving a specified amount of trailing twelve months net product revenue, and (ii) assuming there has been no event of default under the Solar Facility prior to such election. Once the net product revenue condition has been satisfied, the Company may only make an election to borrow under the Term B Loan portion of the Solar Facility until the earlier of (a) December 15, 2021, (b) 30 days following achievement of the net product revenue condition or (c) the occurrence of an event of default.
Oxford Finance LLC \| $35.0 Million Credit Facility
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 35,000,000.0	35,000,000.0		$ 35,000,000.0
Borrowings outstanding under credit facility			$ 35,000,000.0		$ 35,000,000.0
Credit facility maturity date					Feb. 01, 2025
Debt instrument, interest rate			8.15%		8.15%
Debt instrument, final payment fee					$ 2,500,000
Combined debt discount and deferred issuance costs			$ 600,000		$ 600,000
Oxford Finance LLC \| $35.0 Million Credit Facility \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate					7.38%
Debt instrument, description of variable rate basis					30 day U.S. LIBOR
Oxford Finance LLC \| $35.0 Million Credit Facility \| Term A Loan
Debt Instrument [Line Items]
Borrowings outstanding under credit facility		$ 25,000,000
Final payment fees percentage		8.50%
Oxford Finance LLC \| $35.0 Million Credit Facility \| Term B Loan
Debt Instrument [Line Items]
Borrowings outstanding under credit facility		$ 5,000,000.0
Final payment fees percentage		7.50%
Oxford Finance LLC \| $35.0 Million Credit Facility \| Term C Loan
Debt Instrument [Line Items]
Line of credit facility, current borrowing capacity		$ 5,000,000.0