Common Stock	6 Months Ended
Jun. 30, 2013
Equity [Abstract]
Common Stock	Note 10. Common Stock In June 2009, we entered into a sales agreement (2009 sales agreement) pursuant to which we had the option to sell up to $30 million of our common stock, from time to time, in at-the-market offerings. Between June 2009 and November 2012, we sold common stock under the 2009 sales agreement worth approximately $26.7 million. In December 2012, we amended the 2009 sales agreement (2012 amended sales agreement) to, among other provisions, raise the dollar amount of shares available to sell under the agreement back to $30 million. The sales agent is paid compensation of up to 3% of gross proceeds pursuant to the terms of the agreement. The sales agreement, as amended, has been filed with the SEC. In the first and second quarter of 2013, we sold a total of 1,021,074 shares of our common stock at an average price per share of $2.02 for gross proceeds of approximately $2,068,000. The shares were sold under the 2012 amended sales agreement. The shares were offered under our shelf registration statement previously filed with, and declared effective by, the SEC. In the first quarter of 2013, an aggregate of 334,534 Series A Warrants were exercised. For the exercise of these warrants, we issued 334,534 shares of our common stock and received gross proceeds of approximately $468,000. In June 2013, we entered into an agreement with an institutional investor, under which we have the right to sell up to $30.0 million of common stock to the institutional investor. Proceeds from any sales of stock will be used for general corporate purposes. Under the terms of the agreement, we immediately sold 1,645,639 in shares of our common stock to the institutional investor at a purchase price of $1.823 per share, which was the average of the prior ten trading days’ volume weighted average price, and received gross proceeds of $3.0 million. In consideration for entering into the agreement, we issued 329,131 shares of our common stock to the institutional investor. We will not receive any cash proceeds from the issuance of these 329,131 shares. Under this agreement, we have the right for a period of three years and at our sole discretion, to sell additional amounts up to $27.0 million of common stock to the institutional investor subject to certain limitations. The agreement may be terminated by us at any time without any cost or penalty. No warrants will be issued in connection with this transaction. All shares sold or to be sold are offered under our shelf registration statement previously filed with, and declared effective by, the SEC.

Common Stock

6 Months Ended

Jun. 30, 2013

Note 10. Common Stock

In June 2009, we entered into a sales agreement (2009 sales agreement) pursuant to which we had the option to sell up to $30 million of our common stock, from time to time, in at-the-market offerings. Between June 2009 and November 2012, we sold common stock under the 2009 sales agreement worth approximately $26.7 million. In December 2012, we amended the 2009 sales agreement (2012 amended sales agreement) to, among other provisions, raise the dollar amount of shares available to sell under the agreement back to $30 million. The sales agent is paid compensation of up to 3% of gross proceeds pursuant to the terms of the agreement. The sales agreement, as amended, has been filed with the SEC. In the first and second quarter of 2013, we sold a total of 1,021,074 shares of our common stock at an average price per share of $2.02 for gross proceeds of approximately $2,068,000. The shares were sold under the 2012 amended sales agreement. The shares were offered under our shelf registration statement previously filed with, and declared effective by, the SEC.

In the first quarter of 2013, an aggregate of 334,534 Series A Warrants were exercised. For the exercise of these warrants, we issued 334,534 shares of our common stock and received gross proceeds of approximately $468,000.

In June 2013, we entered into an agreement with an institutional investor, under which we have the right to sell up to $30.0 million of common stock to the institutional investor. Proceeds from any sales of stock will be used for general corporate purposes. Under the terms of the agreement, we immediately sold 1,645,639 in shares of our common stock to the institutional investor at a purchase price of $1.823 per share, which was the average of the prior ten trading days’ volume weighted average price, and received gross proceeds of $3.0 million. In consideration for entering into the agreement, we issued 329,131 shares of our common stock to the institutional investor. We will not receive any cash proceeds from the issuance of these 329,131 shares. Under this agreement, we have the right for a period of three years and at our sole discretion, to sell additional amounts up to $27.0 million of common stock to the institutional investor subject to certain limitations. The agreement may be terminated by us at any time without any cost or penalty. No warrants will be issued in connection with this transaction. All shares sold or to be sold are offered under our shelf registration statement previously filed with, and declared effective by, the SEC.