Credit Facilities (Details)				1 Months Ended	3 Months Ended		6 Months Ended
	Feb. 03, 2016 shares	Nov. 02, 2015 USD ($) $ / shares	Dec. 10, 2013 USD ($) $ / shares $ / security	Feb. 29, 2016 USD ($)	Jun. 30, 2016 USD ($) $ / shares shares	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) d $ / shares shares	Jun. 30, 2015 USD ($)	Jun. 02, 2016 shares	Dec. 31, 2015 USD ($) shares	Jul. 21, 2015 USD ($)
Line of Credit Facility [Line Items]
Convertible notes					$ 172,352,000		$ 172,352,000			$ 167,748,000
Payments of derivative issuance costs			$ 7,400,000
Change in fair value of derivative liabilities					$ 38,743,000	$ 0	$ 43,831,000	$ 0
Common stock authorized (in shares) | shares					135,000,000		135,000,000		100,000,000	135,000,000
Adjustments to additional paid-in capital, conversion features of Senior Notes					$ 68,600,000
Revolving Credit Facility | Bank of America
Line of Credit Facility [Line Items]
Aggregate maximum borrowing capacity											$ 20,000,000
Minimum current ratio							1.5
Letter of Credit | Bank of America
Line of Credit Facility [Line Items]
Aggregate maximum borrowing capacity											$ 10,000,000
Convertible Debt
Line of Credit Facility [Line Items]
Reclassification of conversion features to derivative liabilities				$ 24,800,000
2.25% Convertible Senior Notes | Convertible Debt
Line of Credit Facility [Line Items]
Debt instrument face amount			86,250,000
Stated interest rate					2.25%		2.25%
Proceeds from convertible debt			82,600,000
Conversion of convertible securities							41.6051
Redemption price percentage							100.00%
Violation or event of default, declaration by note holders, percentage							25.00%
Fair value disclosure			66,900,000
Beneficial conversion feature			19,300,000
Unamortized discount			3,700,000
Convertible notes			$ 86,300,000		$ 75,900,000		$ 75,900,000
Deferred finance costs, noncurrent, net					$ 1,700,000		$ 1,700,000
Convertible conversion price | $ / shares			$ 24.04		$ 24.04		$ 24.04
Cap price | $ / security			29.02
3.25% Convertible Senior Notes | Convertible Debt
Line of Credit Facility [Line Items]
Debt instrument face amount		$ 125,000,000.0
Stated interest rate					3.25%		3.25%
Threshold trading days | d							20
Threshold consecutive trading days							30 days
Threshold consecutive business days							5 days
Threshold percentage of stock price trigger							130.00%
Threshold business days | d							5
Conversion of convertible securities		89.4314
Redemption price percentage		98.00%					100.00%
Fair value disclosure		$ 97,800,000
Beneficial conversion feature		27,200,000
Unamortized discount		2,900,000
Convertible notes		$ 125,000,000			$ 100,800,000		$ 100,800,000
Deferred finance costs, noncurrent, net					$ 2,600,000		$ 2,600,000
Convertible conversion price | $ / shares		$ 11.18
Redemption, Period One | 2.25% Convertible Senior Notes | Convertible Debt
Line of Credit Facility [Line Items]
Threshold trading days | d							20
Threshold consecutive trading days							30 days
Threshold percentage of stock price trigger							130.00%
Redemption price percentage							100.00%
Redemption, Period Two | 2.25% Convertible Senior Notes | Convertible Debt
Line of Credit Facility [Line Items]
Threshold trading days | d							20
Threshold consecutive trading days							5 years
Threshold consecutive business days							30 days
Threshold percentage of stock price trigger							98.00%
Threshold business days | d							5
Other Assets | 2.25% Convertible Senior Notes | Convertible Debt
Line of Credit Facility [Line Items]
Unamortized discount			$ 2,900,000
Other Assets | 3.25% Convertible Senior Notes | Convertible Debt
Line of Credit Facility [Line Items]
Unamortized discount		$ 3,700,000
Additional Paid-in Capital | 2.25% Convertible Senior Notes | Convertible Debt
Line of Credit Facility [Line Items]
Unamortized discount			$ 800,000
Additional Paid-in Capital | 3.25% Convertible Senior Notes | Convertible Debt
Line of Credit Facility [Line Items]
Unamortized discount		$ 800,000
Minimum | Revolving Credit Facility | Bank of America
Line of Credit Facility [Line Items]
Liquidation proceeds, monetary amount							$ 30,000,000
Unencumbered liquid assets, cash conversion period							5 days
Minimum | 2.25% Convertible Senior Notes | Convertible Debt
Line of Credit Facility [Line Items]
Periodic interest payment							$ 5,700,000
Minimum | 3.25% Convertible Senior Notes | Convertible Debt
Line of Credit Facility [Line Items]
Periodic interest payment							9,100,000
Maximum | 2.25% Convertible Senior Notes | Convertible Debt
Line of Credit Facility [Line Items]
Periodic interest payment							6,900,000
Maximum | 3.25% Convertible Senior Notes | Convertible Debt
Line of Credit Facility [Line Items]
Periodic interest payment							$ 10,700,000
Accounting Standards Update 2015-03 | Other Assets | 2.25% Convertible Senior Notes | Convertible Debt
Line of Credit Facility [Line Items]
Debt issuance costs, net										$ (1,900,000)
Accounting Standards Update 2015-03 | Other Assets | 3.25% Convertible Senior Notes
Line of Credit Facility [Line Items]
Debt issuance costs, net										(2,900,000)
Accounting Standards Update 2015-03 | Long-term Debt | 2.25% Convertible Senior Notes | Convertible Debt
Line of Credit Facility [Line Items]
Debt issuance costs, net										1,900,000
Accounting Standards Update 2015-03 | Long-term Debt | 3.25% Convertible Senior Notes | Convertible Debt
Line of Credit Facility [Line Items]
Debt issuance costs, net										$ 2,900,000
TriVascular Technologies, Inc.
Line of Credit Facility [Line Items]
Equity consideration issued in merger (in shares) | shares	13,586,503