On June 30, 2020, the Company issued 1,718 shares of common stock, in aggregate, for debt conversions of $1,000 aggregate principal amount of the 8% Notes, related shares of Series C Preferred Stock, and of $4,185 aggregate principal amount of the 10% Note. The Company also issued 93 shares of common stock for Series C Preferred Stock discussed above (Note 10).

Restricted Stock

The Company did not grant restricted stock during the three-month periods ended December 31, 2020 and 2019. Stock-based compensation expense attributable to restricted stock was $176 and $757 during the three-month periods ended December 31, 2020 and 2019, respectively. As of December 31, 2020, there was approximately $641 of unrecognized compensation expense related to restricted stock outstanding.

Warrants

No warrants were granted or exercised during the three-month periods ended December 31, 2020 and 2019.

Stock Options

As of December 31, 2020, there were stock options outstanding under the Company’s Amended and Restated 2013 Incentive Stock Plan. During fiscal 2020, 2013 Incentive Stock Plan was amended to increase available balance by 1,000 stock options. Compensation Committee of the Board of Directors authorized to grant either incentive or non-statutory stock options to employees. Vesting periods are established by the Compensation Committee at the time of grant. All stock options outstanding as of December 31, 2020 and September 30, 2020 were non-statutory stock options, had exercise prices equal to the market price on the date of grant, and had expiration dates ten years from the date of grant.

Stock-based compensation expense attributable to stock options and warrants was $135 and $(160) for the three-month periods ended December 31, 2020 and 2019, respectively. As of December 31, 2020, there was approximately $534 of unrecognized compensation expense related to unvested stock options outstanding, and the weighted average vesting period for those options was 3.96 years.