Loss Per Common Share - Computation of Basic and Diluted Net Income (Loss) Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator:
Net income (loss)	$ (8,928)	$ 23,670	$ (13,279)	$ (20,402)	$ (365)	$ (19,452)	$ 1,463	$ (40,219)
Adjustments for basic income (loss) per common share:
Dividend accrued on redeemable preferred stock	(10,190)	$ (10,213)	$ (9,511)	(8,889)	$ (8,689)	$ (8,307)
Deemed dividend	(231,812)						(231,812)
Dividend requirements	(75)			(75)			(225)	(225)
Net loss attributable to common stockholders	$ (251,504)			$ (29,874)			$ (262,011)	$ (67,846)
Denominator:
Denominator for basic and diluted net income (loss) per common share - adjusted weighted-average shares	39,351,875			36,675,477			37,752,342	36,654,416
Basic and dilutive net loss per common share	$ (6.39)			$ (0.81)			$ (6.94)	$ (1.85)
Series E Redeemable Preferred Stock [Member]
Adjustments for basic income (loss) per common share:
Dividend accrued on redeemable preferred stock	$ (10,190)			$ (8,889)			$ (29,914)	$ (25,885)
Accretion of redeemable preferred stock	(499)			(508)			(1,523)	(1,517)
Series E and Series F Redeemable Preferred Stock [Member]
Adjustments for basic income (loss) per common share:
Deemed dividend	(231,812)						(231,812)
Series B Preferred Stock [Member]
Adjustments for basic income (loss) per common share:
Dividend requirements	(60)			(60)			(180)	(180)
Series D Preferred Stock [Member]
Adjustments for basic income (loss) per common share:
Dividend requirements	$ (15)			$ (15)			$ (45)	$ (45)