Net Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2017

Disclosure Potential Common Shares Excluded From Computation Of Diluted Net Loss Per Share [Abstract]

Potential Common Shares Excluded from Computation of Diluted Net Loss per Share

Potential dilutive common share equivalents consist of the following:

	Years Ended December 31,
	2017	2016	2015
1.375% Convertible Senior Notes	4,319,429	—	—
2.00% Convertible Senior Notes	78,783	1,442,433	4,327,257
1.25% Convertible Senior Notes	5,910,954	5,910,954	—
Unvested restricted stock units	994,364	962,219	811,965
Outstanding stock options	3,377,220	3,441,303	2,999,199
Total dilutive common shares	14,680,750	11,756,909	8,138,421