Stockholders' Equity (Details) - USD ($)				3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 07, 2017	Apr. 17, 2017	Apr. 03, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Jan. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of preferred share purchase rights for each outstanding share of common stock		1
Common stock, par value (in dollars per share)		$ 0.01		$ 0.01		$ 0.01		$ 0.01
Preferred stock, par value (in dollars per share)		0.01		0.01		0.01		$ 0.01
Initial exercise price (in usd per share)		$ 80		$ 34.12		$ 34.12
Number of preferred share, called by each right		0.001
Preferred stock, economic equivalent to common stock (in shares)		1,000
Period following public announcement of an acquiring person		10 days
Period following intention of a tender offer		10 days
Covenant, consolidated assets sold		50.00%
Multiplier for shares calculation upon acquisition		2
Share repurchase program, authorized amount									$ 60,000,000.0
Common stock repurchased and retired (in shares)						0		831,744
Stock repurchased and retired during period, value								$ 20,000,000
Average share price (in usd per share)								$ 24.05
Decease in total stockholders' equity						$ 134,100,000
Increase related to net shares issued in connection with license agreement, value						12,555,000	$ 0
Increase related to equity-based compensation expense						18,100,000
Net loss				$ 152,061,000	$ (16,196,000)	202,688,000	$ (8,074,000)
Reduction for changes in deferred taxes associated with debt						27,200,000
Convertible Notes | Convertible Notes due 2022
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase related to equity component of debt repurchased						72,600,000
Reduction related to equity component for debt issuance costs	$ 2,200,000					2,200,000
Convertible Notes | Convertible Notes due 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reduction related to equity component of debt						28,300,000
Endoceutics License Agreement
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase related to net shares issued in connection with license agreement, value			$ 13,500,000			$ 13,500,000
Accounting Standards Update 2016-09, Excess Tax Benefit Component | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase related to cumulative- effect adjustment								$ 21,600,000
Common Stock
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Maximum majority ownership, resulting from 2017 net operating loss rights agreement		4.99%				4.99%