Stockholders' Equity

12 Months Ended

Dec. 31, 2015

Equity [Abstract]

Stockholders' Equity

6. STOCKHOLDERS’ EQUITY

Common Stock

As of December 31, 2015 the Company had reserved 3,305,589 shares of common stock for issuance upon the exercise of outstanding common stock options and vesting of restricted stock units. Also, 732,270 shares of the Company’s common stock were reserved for future grants of stock options and restricted stock units (or other similar equity instruments) under the Company’s 2007 Stock Incentive Plan (the “2007 Plan”) as of December 31, 2015. In addition, 24,380 shares of the Company’s common stock were reserved for future exercise of outstanding warrants as of December 31, 2015.

On January 13, 2014, the Company completed a public offering of common stock in which a total of 3,047,500 shares were sold, including 397,500 shares pursuant to the full exercise of the underwriter’s over-allotment option, at a price of $10.65 per share. The Company raised a total of $32.5 million in gross proceeds from the offering, or approximately $30.3 million in net proceeds after deducting the underwriting discount and expenses of $2.3 million.

On March 20, 2014, certain stockholders of the Company completed a public offering of 2,875,000 shares of common stock and the Company sold 375,000 shares pursuant to the full exercise of the underwriter’s over-allotment option each at a price of $13.00 per share. The Company raised a total of $4.9 million in gross proceeds from the offering, or approximately $4.4 million in net proceeds after deducting the underwriting discount and expenses of $319,000 and estimated costs of $148,000.

Warrants

At December 31, 2015 and 2014, the Company had outstanding 24,380 and 267,826 warrants, respectively, to purchase shares of common stock at an exercise price of $3.65 per share. The warrants were issued in conjunction with the issuance of convertible promissory notes issued by the Company to investors from August 2005 through October 2005. The warrants are immediately exercisable and expire 10 years from the date of issuance. For the year ended December 31, 2015, 243,336 warrants expired.

Treasury Stock

The treasury shares are accounted for using the cost method whereby the entire cost of the acquired stock is recorded as treasury stock. The Company did not repurchase any shares for the twelve months ended December 31, 2015 and 2014.