Stockholders' Equity	6 Months Ended
Jun. 30, 2018
Stockholders' Equity
Stockholders' Equity	8.Stockholders’ Equity Preferred Stock As of June 30, 2018, the Company had 5,000,000 shares of preferred stock authorized for issuance, $0.001 par value per share, with none issued or outstanding. Preferred stock may be issued from time to time in one or more series, each series to have such terms as stated or expressed in the resolutions providing for the issue of such series adopted by the board of directors of the Company. Preferred stock which may be redeemed, purchased or acquired by the Company may be reissued except as otherwise provided by law. Common Stock Warrants June 2018 Warrants In the June 2018 Financing, the Company issued warrants to purchase 42,000,000 shares of common stock at an exercise price of $1.20 per share, which were immediately exercisable upon issuance, and will expire five years from the date of issuance. The terms of the warrants include certain provisions related to fundamental transactions, a cashless exercise provision in the event registered shares are not available and do not include any mandatory redemption provisions. Therefore, the warrants have been classified in stockholders’ equity. Any changes to fair value of the warrants will not be recognized so long as the warrants continue to be equity classified. As of June 30, 2018, all warrants related to this transaction were outstanding with a contractual life of 4.98 years. Warrants Associated with the Term Loan In conjunction with the term loans (Note 6), the Company issued warrants to purchase 315,688 shares of series B convertible preferred stock. Upon the closing of the Company’s initial public offering (the “IPO”) in June 2015, the warrants were automatically converted into warrants to purchase an aggregate of 24,566 shares of Common Stock at an exercise price of $12.21 per share. As of June 30, 2018, all warrants related to this transaction were outstanding with a weighted average contractual life of 3.45 years.

8.Stockholders’ Equity

Preferred Stock

As of June 30, 2018, the Company had 5,000,000 shares of preferred stock authorized for issuance, $0.001 par value per share, with none issued or outstanding. Preferred stock may be issued from time to time in one or more series, each series to have such terms as stated or expressed in the resolutions providing for the issue of such series adopted by the board of directors of the Company. Preferred stock which may be redeemed, purchased or acquired by the Company may be reissued except as otherwise provided by law.

Common Stock Warrants

June 2018 Warrants

In the June 2018 Financing, the Company issued warrants to purchase 42,000,000 shares of common stock at an exercise price of $1.20 per share, which were immediately exercisable upon issuance, and will expire five years from the date of issuance.

The terms of the warrants include certain provisions related to fundamental transactions, a cashless exercise provision in the event registered shares are not available and do not include any mandatory redemption provisions. Therefore, the warrants have been classified in stockholders’ equity. Any changes to fair value of the warrants will not be recognized so long as the warrants continue to be equity classified.

As of June 30, 2018, all warrants related to this transaction were outstanding with a contractual life of 4.98 years.

Warrants Associated with the Term Loan

In conjunction with the term loans (Note 6), the Company issued warrants to purchase 315,688 shares of series B convertible preferred stock. Upon the closing of the Company’s initial public offering (the “IPO”) in June 2015, the warrants were automatically converted into warrants to purchase an aggregate of 24,566 shares of Common Stock at an exercise price of $12.21 per share. As of June 30, 2018, all warrants related to this transaction were outstanding with a weighted average contractual life of 3.45 years.