Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2020

Fair Value Disclosures [Abstract]

Schedule of Fair Value Measurements at Reporting Date

(in thousands)	As of December 31, 2020
	Carrying Value		Fair Value
			Level 1		Level 2		Level 3
Revolving credit facility	$	130,000	$	—	$	130,000	$	—

(in thousands)	As of December 31, 2019
	Carrying Value		Fair Value
			Level 1		Level 2		Level 3
Revolving credit facility	$	39,527	$	—	$	39,527	$	—
Unsecured Senior Notes	54,765		—		—		54,600

Summary of Change in the Estimated Fair Value of Private Placement Warrants

The following table summarizes changes in the estimated fair value of the Company’s warrant liability:

(in thousands)	December 31, 2019
Balance at beginning of year	$	35,100
Change in value of warrants *	1,352
Settlement of warrants	(36,452)
Balance at end of year	$	—

*     The change in value of the warrant liability is presented in Loss from change in value and exercise of warrants in the Company’s Consolidated Statements of Operations. The change in value for the year ended December 31, 2019 includes the impact of Weichai exercising the warrant in April 2019.