Stockholders' Equity and Stock Incentive Plans - Summary of Stock Option Activity (Details)	9 Months Ended
	Sep. 30, 2020 $ / shares shares
Stock Options Outstanding
Stock Options Outstanding, Beginning of year (in shares) | shares	3,126,521
Stock Options Outstanding, Granted (in shares) | shares	0
Stock Options Outstanding, Exercised (in shares) | shares	(45,000)
Stock Options Outstanding, Cancelled (in shares) | shares	(2,292)
Stock Options Outstanding, Expired (in shares) | shares	(148,013)
Stock Options Outstanding, End of year (in shares) | shares	2,931,216
Stock Options Outstanding, Exercisable (in shares) | shares	2,847,738
Weighted-Average Exercise Price
Weighted-Average Exercise Price, Beginning of year (USD per share) | $ / shares	$ 11.61
Weighted-Average Exercise Price, Granted (USD per share) | $ / shares	0
Weighted-Average Exercise Price, Exercised (USD per share) | $ / shares	2.66
Weighted-Average Exercise Price, Cancelled (USD per share) | $ / shares	13.50
Weighted-Average Exercise Price, Expired (USD per share) | $ / shares	26.61
Weighted-Average Exercise Price, End of year (USD per share) | $ / shares	10.99
Weighted-Average Exercise Price, Exercisable (USD per share) | $ / shares	$ 10.92