Debt - Additional Information (Details)		1 Months Ended							6 Months Ended
	Jun. 14, 2017 USD ($)	Jul. 31, 2020 USD ($)	Aug. 31, 2019 USD ($)	Jul. 31, 2019	May 31, 2019 USD ($)	Apr. 30, 2019	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2020 USD ($) $ / shares		Jun. 30, 2020 USD ($)		Aug. 31, 2017 USD ($)
Debt
Common stock value									$ 93,000		$ 91,000
Principal amount of the Notes									191,661,000		202,094,000
Debt discount costs									8,854,000		9,991,000
Principal prepayment of term loan									10,000,000
Term Loan Facility due December 2022
Debt
Principal amount of the Notes									79,948,000		89,093,000
Debt discount costs									3,713,000		3,311,000
Term Loan Agreement
Debt
Principal prepayment of term loan		$ 10,000,000.0
Amendment fee		$ 500,000
Revolving Credit Facility
Debt
Principal amount of the Notes									26,713,000	[1]	$ 28,001,000	[2]
Initial borrowing capacity	$ 52,000,000.0
Minimum drawn balance (as a percent)	30.00%
Outstanding revolving credit facility									26,700,000
Revolving Credit Facility | Revolving Credit Agreement
Debt
Reduced borrowing capacity								$ 32,000,000.0
Term loan
Debt
Principal amount of the Notes									$ 79,900,000
Term loan | Term Loan Facility due December 2022
Debt
Initial term loan borrowing capacity								40,000,000.0
Additional term loan borrowing capacity								$ 20,000,000.0
Loan prepayment fees for first year (percentage)								3.00%
Loan prepayment fees for second year (percentage)								2.00%
Loan prepayment fees for third year (percentage)								1.00%
Term Loan (in months)								60 months
Term of interest payable (in months)								24 months
Administrative fee payable on term loan as a percentage								0.25%
Final payment of administrative fee payable on term loan as a percentage								4.00%
Debt instrument amount withdrawn							$ 5,000,000.0
Debt instrument scheduled commitment extended termination date							Jun. 30, 2019
Debt instrument remaining unfunded commitment amount							$ 15,000,000.0
Term loan | Term Loan Facility Due May 2024
Debt
Debt instrument increased commitment amount			$ 25,000,000		$ 500,000
Debt discount costs			$ 1,600,000		$ 1,500,000
90-day LIBOR | Revolving Credit Facility
Debt
Interest rate determination basis									90-day LIBOR
Variable rate (as a percent)	4.50%				3.50%	4.50%
90-day LIBOR | Term loan | Term Loan Facility due December 2022
Debt
Interest rate determination basis									90-day LIBOR
Variable rate (as a percent)								6.75%
90-day LIBOR | Term loan | Term Loan Facility Due May 2024
Debt
Interest rate determination basis									90-day LIBOR
Variable rate (as a percent)			6.75%	5.50%	5.50%	6.75%
3.75% Convertible Senior Notes due 2022
Debt
Interest rate (as a percent)									3.75%		3.75%		3.75%
Conversion rate, number of shares to be issued per $1000 of principal amount (in shares)									174.8252
Principal amount used for debt instrument conversion ratio									$ 1,000
Conversion price (in dollars per share) | $ / shares									$ 5.72
Aggregate principal amount of debt issued													$ 85,000,000.0
Repurchase price, as a percentage of the principal amount, in the event of a fundamental change, as defined in Indenture									100.00%
Principal amount of the Notes									$ 85,000,000		$ 85,000,000
Debt discount costs									$ 5,141,000		$ 6,680,000

[1] Unamortized debt costs of $0.8 million recorded in other assets on the consolidated balance sheet.

[2] Unamortized debt costs of $0.9 million recorded in other assets on the consolidated balance sheet.