Stock-Based Compensation - Stock Options and Appreciation Rights (Details)	3 Months Ended
	Mar. 31, 2024 $ / shares shares
2023 Inducement Plan
Stock Options
Outstanding, beginning balance (in shares) | shares	422,800
Granted (in shares) | shares	0
Exercised (in shares) | shares	0
Canceled (in shares) | shares	0
Outstanding, ending balance (in shares) | shares	422,800
Shares exercisable (in shares) | shares	101,762
Weighted-Average Exercise Price
Outstanding, beginning balance (in usd per share) | $ / shares	$ 10.67
Granted (in usd per share) | $ / shares	0
Exercised (in usd per share) | $ / shares	0
Canceled (in usd per share) | $ / shares	0
Outstanding, ending balance (in usd per share) | $ / shares	10.67
Shares exercisable (in usd per share) | $ / shares	$ 11.08
2015 Plan
Stock Options
Outstanding, beginning balance (in shares) | shares	4,787,042
Granted (in shares) | shares	594,367
Exercised (in shares) | shares	(142)
Canceled (in shares) | shares	(284,823)
Outstanding, ending balance (in shares) | shares	5,096,444
Shares exercisable (in shares) | shares	3,411,898
Weighted-Average Exercise Price
Outstanding, beginning balance (in usd per share) | $ / shares	$ 38.10
Granted (in usd per share) | $ / shares	5.39
Exercised (in usd per share) | $ / shares	5.22
Canceled (in usd per share) | $ / shares	37.60
Outstanding, ending balance (in usd per share) | $ / shares	34.31
Shares exercisable (in usd per share) | $ / shares	$ 41.21
2005 Plan
Stock Options
Outstanding, beginning balance (in shares) | shares	58,275
Granted (in shares) | shares	0
Exercised (in shares) | shares	0
Canceled (in shares) | shares	(57,569)
Outstanding, ending balance (in shares) | shares	706
Shares exercisable (in shares) | shares	706
Weighted-Average Exercise Price
Outstanding, beginning balance (in usd per share) | $ / shares	$ 119.79
Granted (in usd per share) | $ / shares	0
Exercised (in usd per share) | $ / shares	0
Canceled (in usd per share) | $ / shares	120.01
Outstanding, ending balance (in usd per share) | $ / shares	102.11
Shares exercisable (in usd per share) | $ / shares	$ 102.11