LOSS PER COMMON SHARE	6 Months Ended
Jun. 30, 2018
Earnings Per Share [Abstract]
LOSS PER COMMON SHARE	8. LOSS PER COMMON SHARE Basic and diluted net loss per common share is calculated by dividing net loss applicable to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration of common stock equivalents. The Company’s potentially dilutive shares, which include outstanding stock options, unvested RSUs, and shares issuable upon conversion of the 2024 Notes, are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive. Outstanding stock options, unvested RSUs and PRSUs of approximately 7.5 million and 5.0 million were excluded from the calculation of diluted net loss per share for the second quarter and first six months of 2018 and 2017, respectively, due to their anti-dilutive effect. In May 2017, the Company issued $517.5 million of convertible debt pursuant to the 2024 Notes, which under certain circumstances may convert to common shares outstanding. If converted, this $517.5 million of convertible debt would represent approximately 6.8 million common shares. See Note 5, Convertible Senior Notes, for additional information. As provided by the terms of the indenture underlying the 2024 Notes, the Company has a choice to settle the conversion obligation for the 2024 Notes in cash, shares or any combination of cash and shares. The Company currently intends to settle the par value of the 2024 Notes in cash and any excess conversion premium in shares. Accordingly, the par value of the 2024 Notes will not be included in the calculation of diluted income per share, but the dilutive effect of the conversion premium, if any, will be considered in the calculation of diluted net income per share using the treasury stock method.

8. LOSS PER COMMON SHARE

Basic and diluted net loss per common share is calculated by dividing net loss applicable to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration of common stock equivalents. The Company’s potentially dilutive shares, which include outstanding stock options, unvested RSUs, and shares issuable upon conversion of the 2024 Notes, are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive. Outstanding stock options, unvested RSUs and PRSUs of approximately 7.5 million and 5.0 million were excluded from the calculation of diluted net loss per share for the second quarter and first six months of 2018 and 2017, respectively, due to their anti-dilutive effect.

In May 2017, the Company issued $517.5 million of convertible debt pursuant to the 2024 Notes, which under certain circumstances may convert to common shares outstanding. If converted, this $517.5 million of convertible debt would represent approximately 6.8 million common shares. See Note 5, Convertible Senior Notes, for additional information. As provided by the terms of the indenture underlying the 2024 Notes, the Company has a choice to settle the conversion obligation for the 2024 Notes in cash, shares or any combination of cash and shares. The Company currently intends to settle the par value of the 2024 Notes in cash and any excess conversion premium in shares. Accordingly, the par value of the 2024 Notes will not be included in the calculation of diluted income per share, but the dilutive effect of the conversion premium, if any, will be considered in the calculation of diluted net income per share using the treasury stock method.