Loss Per Share (Details)		12 Months Ended
	Mar. 27, 2018 USD ($)	Dec. 31, 2019 shares	Dec. 31, 2018 shares	Dec. 31, 2017 shares	Apr. 04, 2018 USD ($)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive common stock instruments outstanding (shares)		10,147,000	8,167,000	7,352,000
Conversion ratio	0.0323428
Shares issued (shares)		0
Repurchase of common stock under prepaid forward contract (shares)		1,858,500
Shares issuable upon the release of restricted stock awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive common stock instruments outstanding (shares)		14,000	76,000	24,000
Shares issuable upon exercise of stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive common stock instruments outstanding (shares)		10,133,000	8,091,000	7,328,000
Maximum
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares issued (shares)		5,500,000
Unsecured Obligations | 2.50% Convertible Notes due 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Aggregate principal amount | $	$ 150,000,000				$ 171,500,000
Conversion multiple | $					$ 1,000