Net Loss per Share (Tables)

6 Months Ended

Jun. 30, 2019

Earnings Per Share [Abstract]

Potentially Dilutive Securities Excluded from Computation of Diluted Weighted-Average Shares

Potential common stock equivalents excluded from the calculation of diluted earnings per share because the effect would have been anti-dilutive were as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
Stock options		11,552,639		7,750,244		11,552,639		7,750,244
Warrants		486,812		20,671,036		486,812		20,671,036
Restricted stock units		1,376,364		1,398,129		1,376,364		1,398,129
Performance stock units		301,666		466,668		301,666		466,668
Deferred stock units		417		35,001		417		35,001
		13,717,898		30,321,078		13,717,898		30,321,078