Stock Options

The following table summarizes stock option transactions for the six months ended June 30, 2020:

Common Stock Warrants

Warrant transactions for the six months ended June 30, 2020 are as follows:

Settlement Warrants

Pursuant to the Settlement Agreement, the Company issued pre-funded warrants to purchase up to an aggregate of 5,500,000 shares of common stock (the “Settlement Warrants”) at an exercise price of $0.20 per share, subject to adjustment in certain circumstances. The Settlement Warrants expire on June 19, 2025. The aggregate exercise price of the Settlement Warrants was deemed to be pre-funded to the Company in conjunction with exchange of previously issued warrants to purchase 480,352 shares of common stock pursuant to the Settlement Agreement. Exercise of the Settlement Warrant is subject to certain additional terms and conditions, including certain beneficial ownership limitations.

Forbearance Agreements

Pursuant to the Forbearance Agreements, (i) the exercise price of all warrants to purchase common stock held by holders of the Default Notes will be reduced to equal the conversion price of the Default Notes and (ii) the number of shares of common stock underlying such warrants shall be increased so that the total exercise price of all such warrants after the decrease in the exercise price equals the total exercise price of all such warrants prior to the decrease in the exercise price. Further, the expiration date of all such warrants shall be extended for three years following the closing date of any New Financing.