In connection with the Securities Purchase Agreement (see Note 13), the Company issued and sold an aggregate of 5,411,687 pre-funded warrants exercisable for an aggregate of 5,411,687 shares of common stock. The total exercise price of the pre-funded warrants is $0.65 per share, $0.64 of which was pre-funded and paid to the Company upon issuance of the pre-funded warrants. The remaining exercise price of the pre-funded warrants is $0.01 per share. In March 2020, 3,176,762 of the pre-funded warrants were exercised for proceeds of $31,768. The remaining pre-funded warrants are immediately exercisable and do not expire. As the remaining shares underlying the pre-funded warrants are issuable for nominal consideration of $0.01 per share, 2,234,925 and 0 unexercised pre-funded warrants were considered outstanding for purposes of the calculation of loss per share, as of March 31, 2020 and 2019, respectively.

The following outstanding options, warrants, restricted stock units and debt conversion option were excluded from the computation of diluted net loss per share for the periods presented because their effect would have been anti-dilutive:

	Three Months Ended March 31,
	2020		2019
Options to purchase common stock		4,156,989		1,977,787
Common stock warrants		236,915		236,915
Restricted stock units		210,303		229,581
QNAH convertible note		805,991		783,339