TWO Quarterly report pursuant to Section 13 or 15(d)

Convertible Senior Notes	9 Months Ended
Convertible Senior Notes	Sep. 30, 2017
Debt Disclosure [Abstract]
Convertible Senior Notes	Convertible Senior Notes On January 19, 2017, the Company closed an underwritten public offering of $287.5 million aggregate principal amount of convertible senior notes due 2022, which included $37.5 million aggregate principal amount sold by the Company to the underwriter of the offering pursuant to an overallotment option. The net proceeds from the offering were approximately $282.2 million after deducting underwriting discounts and estimated offering expenses payable by the Company. The notes are unsecured, pay interest semiannually at a rate of 6.25% per annum and are convertible at the option of the holder into shares of the Company’s common stock. The notes will mature in January 2022, unless earlier converted or repurchased in accordance with their terms. The Company does not have the right to redeem the notes prior to maturity, but may be required to repurchase the notes from holders under certain circumstances. As of September 30, 2017, the notes had a conversion rate of 50.2537 shares of common stock per $1,000 principal amount of the notes (based on the retroactive adjustment due to the Company’s one-for-two reverse stock split described in Note 20 - Equity). The outstanding amount due on the convertible senior notes as of September 30, 2017 was $282.5 million, net of deferred issuance costs.