Debt - Net Carrying Amount of Liability Component of Debt Discount (Details) - USD ($)	Jun. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Aggregate principal amount	$ 111,882,000	$ 181,580,000
Less unamortized discounts and debt issuance costs	(2,480,000)	(21,778,000)
Total net carrying value	116,505,000	162,246,000
Term Loan
Debt Instrument [Line Items]
Aggregate principal amount	86,600,000
Revolving Credit Facility
Debt Instrument [Line Items]
Aggregate principal amount	25,000,000	25,000,000
2023 Series D Convertible Notes | Convertible Notes Payable
Debt Instrument [Line Items]
Aggregate principal amount	0	50,323,000
2023 Series D Convertible Notes
Debt Instrument [Line Items]
Deferred gain of the 2023 Series D Notes (due May 2023)	20,000	2,444,000
2023 Series D Convertible Notes | Convertible Notes Payable
Debt Instrument [Line Items]
Aggregate principal amount	277,000	3,352,000
Face amount of the 2023 Loan (due February 2023) | Term Loan
Debt Instrument [Line Items]
Aggregate principal amount	86,605,000	102,905,000
Deferred gain on the 2023 Term Loan (due February 2023)
Debt Instrument [Line Items]
Deferred gain of the 2023 Series D Notes (due May 2023)	$ 7,083,000	$ 0