7.    Subsequent Events

In October 2019, we completed an underwritten public offering (the “Public Offering”) pursuant to which we issued 40,276,000 units at an offering price of $0.225 per unit, consisting of 35,886,000 shares of our common stock and pre-funded warrants to purchase 4,390,000 shares of our common stock with an exercise price of $0.01 per share (the “Pre-funded Warrants"), and Class B Warrants to purchase 40,276,000 shares of our common stock at $0.225 per share (the “Class B Warrants”).  The Pre-Funded Warrants, which were exercised for common stock in October 2019, were issued in lieu of common stock in order to ensure the Purchaser did not exceed certain beneficial ownership limitations. The Class B Warrants are immediately exercisable and will expire in October 2024. The Class B Warrant agency agreement contains a provision where the warrant holder has the option to receive cash equal to the Black Scholes fair value of the remaining unexercised portion of the warrant in the event that there is a fundamental transaction (contractually defined to include various merger, acquisition or stock transfer activities). Through the date of filing this Quarterly Report on Form 10-Q, we received net cash proceeds of approximately $8.1 million, after deduction of underwriting fees and other offering expenses.