7.  Equity and Stock-Based Compensation

Stock-based compensation expense was $0.1 million and $0.2 million in the three months ended December 31, 2019 and 2018, respectively.  Stock-based compensation expense is included in selling, general and administrative expenses.

The following table summarizes our stock option activity during the three months ended December 31, 2019:

The fair value of options was estimated at the applicable grant date using the Black-Scholes option pricing model with the following assumptions:

On November 29, 2018, we announced that our Board approved a stock repurchase program, pursuant to which we may repurchase up to $4 million of our outstanding common stock, par value $0.01 per share, over a one-year period. Repurchases under the program were to be made in open market transactions at prevailing market prices, in privately negotiated transactions, or by other means in compliance with the rules and regulations of the SEC; however, we had no obligation to repurchase shares and the timing, actual number, and value of shares to be repurchased was subject to management’s discretion and depended on the Company’s stock price and other market conditions. Our Board could have terminated the repurchase program at any time while it was in effect.  We intended to retire any repurchased shares.  The term of our repurchase program expired as of the quarter ended December 31, 2019.  There were no shares repurchased during the quarter ended December 31, 2019.