The Company	12 Months Ended
Dec. 31, 2013
Accounting Policies [Abstract]
The Company	1. The Company *Business* We were incorporated in the state of Delaware on December 19, 2000 as FaxMed, Inc., changed our name to Alexza Corporation in June 2001 and in December 2001 became Alexza Molecular Delivery Corporation. In July 2005, we changed our name to Alexza Pharmaceuticals, Inc. We are a pharmaceutical company focused on the research, development, and commercialization of novel proprietary products for the acute treatment of central nervous system conditions. We operate in one business segment. Our facilities and employees are currently located in the United States. In 2012, we transitioned out of the development stage. *Reverse Stock Split* On June 12, 2012, we effected a 1-for-10 reverse stock split of our outstanding common stock resulting in a reduction of our total common stock issued and outstanding from 119.6 million shares to 12.0 million shares. The reverse stock split affected all of the stockholders of our common stock uniformly, and did not materially affect any stockholder’s percentage of ownership interest. The par value of our common stock remained unchanged at $0.0001 per share and the number of authorized shares of common stock remained the same after the reverse stock split. As the par value per share of our common stock remained unchanged at $0.0001 per share, a total of $11,000 was reclassified from common stock to additional paid-in capital. In connection with this reverse stock split, the number of shares of common stock reserved for issuance under our equity incentive, stock option and employee stock purchase plans (see Note 10) as well as the shares of common stock underlying outstanding stock options, restricted stock units and warrants were also proportionately reduced while the exercise prices of such stock options and warrants were proportionately increased. All references to shares of common stock and per share data for all periods presented in the accompanying financial statements and notes thereto have been adjusted to reflect the reverse stock split on a retroactive basis. *Authorized Shares* On July 28, 2011, we filed a Certificate of Amendment to our Restated Certificate of Incorporation to increase the total number of authorized shares from 105,000,000 to 205,000,000 and to increase the total number of authorized shares of common stock from 100,000,000 to 200,000,000. *Underwritten Public Offering* On February 23, 2012, we issued an aggregate of 4,400,000 shares of our common stock and warrants to purchase up to an additional 4,400,000 shares of our common stock in an underwritten public offering. Net proceeds from the offering were $20,231,000, after deducting offering expenses. The warrants are exercisable beginning February 24, 2013, at an exercise price of $5.00 per share, and will expire on February 23, 2017. The shares of common stock and warrants were sold pursuant to a shelf registration statement declared effective by the Securities and Exchange Commission on May 20, 2010. We agreed to customary obligations, including indemnification. *Private Placement* On March 5, 2012, we entered into an amendment to the Collaboration, License and Supply Agreement, or the Ferrer Agreement, with Grupo Ferrer Internacional, S.A., or Ferrer (See Note 8). Ferrer and we agreed to eliminate a future potential milestone payment in exchange for Ferrer’s purchase of $3,000,000 of our common stock. On March 15, 2012 Ferrer purchased 241,936 shares of our common stock for $12.40 per share. We classified $1,452,000 of the proceeds as deferred revenue and are recognizing the amount into revenue over the estimated performance period of the Ferrer Agreement (see Note 8). *Registered Direct Equity Issuances* On May 6, 2011, we issued an aggregate of 1,192,703 shares of its common stock and warrants to purchase up to an additional 417,445 shares of its common stock in a registered direct offering. Net proceeds from the offering were approximately $15,941,000, after deducting offering expenses. The warrants are exercisable at $17.55 per share and will expire on May 6, 2016. The securities were sold pursuant to a shelf registration statement declared effective by the SEC on May 20, 2010. We agreed to customary obligations regarding registration, including indemnification and maintenance of the registration statement. *Equity Financing Facility* In July 2012, we entered into a committed equity line of credit with Azimuth Opportunity, L.P., or Azimuth, pursuant to which we were granted the ability to sell up to $20,000,000 of our common stock over an approximately 24-month period pursuant to the terms of a Common Stock Purchase Agreement, or the Purchase Agreement. In addition to the foregoing amounts, in consideration for the performance of Azimuth’s obligations under the Purchase Agreement, we issued to Azimuth 80,429 shares of its common stock on July 23, 2012. In August and September 2012, we utilized $13,600,000 under the facility by issuing 3,489,860 shares of our common stock to Azimuth at an average price of $3.88 per share, which resulted in $13,393,000 in net proceeds to us. In May 2013, we utilized the remaining $6,400,000 available under the facility by issuing 1,437,481 shares of our common stock to Azimuth at an average price of $4.48 per share, which resulted in $6,347,000 of net proceeds to us. Shares were issued to Azimuth at a discount of 5% to the volume-weighted average price of our common stock over a preceding period of trading days. Shares sold under this facility were sold pursuant to a shelf registration statement declared effective by the SEC on July 3, 2012.

1. The Company

Business

We were incorporated in the state of Delaware on December 19, 2000 as FaxMed, Inc., changed our name to Alexza Corporation in June 2001 and in December 2001 became Alexza Molecular Delivery Corporation. In July 2005, we changed our name to Alexza Pharmaceuticals, Inc.

We are a pharmaceutical company focused on the research, development, and commercialization of novel proprietary products for the acute treatment of central nervous system conditions. We operate in one business segment. Our facilities and employees are currently located in the United States. In 2012, we transitioned out of the development stage.

Reverse Stock Split

On June 12, 2012, we effected a 1-for-10 reverse stock split of our outstanding common stock resulting in a reduction of our total common stock issued and outstanding from 119.6 million shares to 12.0 million shares. The reverse stock split affected all of the stockholders of our common stock uniformly, and did not materially affect any stockholder’s percentage of ownership interest. The par value of our common stock remained unchanged at $0.0001 per share and the number of authorized shares of common stock remained the same after the reverse stock split.

As the par value per share of our common stock remained unchanged at $0.0001 per share, a total of $11,000 was reclassified from common stock to additional paid-in capital. In connection with this reverse stock split, the number of shares of common stock reserved for issuance under our equity incentive, stock option and employee stock purchase plans (see Note 10) as well as the shares of common stock underlying outstanding stock options, restricted stock units and warrants were also proportionately reduced while the exercise prices of such stock options and warrants were proportionately increased. All references to shares of common stock and per share data for all periods presented in the accompanying financial statements and notes thereto have been adjusted to reflect the reverse stock split on a retroactive basis.

Authorized Shares

On July 28, 2011, we filed a Certificate of Amendment to our Restated Certificate of Incorporation to increase the total number of authorized shares from 105,000,000 to 205,000,000 and to increase the total number of authorized shares of common stock from 100,000,000 to 200,000,000.

Underwritten Public Offering

On February 23, 2012, we issued an aggregate of 4,400,000 shares of our common stock and warrants to purchase up to an additional 4,400,000 shares of our common stock in an underwritten public offering. Net proceeds from the offering were $20,231,000, after deducting offering expenses. The warrants are exercisable beginning February 24, 2013, at an exercise price of $5.00 per share, and will expire on February 23, 2017. The shares of common stock and warrants were sold pursuant to a shelf registration statement declared effective by the Securities and Exchange Commission on May 20, 2010. We agreed to customary obligations, including indemnification.

Private Placement

On March 5, 2012, we entered into an amendment to the Collaboration, License and Supply Agreement, or the Ferrer Agreement, with Grupo Ferrer Internacional, S.A., or Ferrer (See Note 8). Ferrer and we agreed to eliminate a future potential milestone payment in exchange for Ferrer’s purchase of $3,000,000 of our common stock. On March 15, 2012 Ferrer purchased 241,936 shares of our common stock for $12.40 per share. We classified $1,452,000 of the proceeds as deferred revenue and are recognizing the amount into revenue over the estimated performance period of the Ferrer Agreement (see Note 8).

Registered Direct Equity Issuances

On May 6, 2011, we issued an aggregate of 1,192,703 shares of its common stock and warrants to purchase up to an additional 417,445 shares of its common stock in a registered direct offering. Net proceeds from the offering were approximately $15,941,000, after deducting offering expenses. The warrants are exercisable at $17.55 per share and will expire on May 6, 2016. The securities were sold pursuant to a shelf registration statement declared effective by the SEC on May 20, 2010. We agreed to customary obligations regarding registration, including indemnification and maintenance of the registration statement.

Equity Financing Facility

In July 2012, we entered into a committed equity line of credit with Azimuth Opportunity, L.P., or Azimuth, pursuant to which we were granted the ability to sell up to $20,000,000 of our common stock over an approximately 24-month period pursuant to the terms of a Common Stock Purchase Agreement, or the Purchase Agreement. In addition to the foregoing amounts, in consideration for the performance of Azimuth’s obligations under the Purchase Agreement, we issued to Azimuth 80,429 shares of its common stock on July 23, 2012. In August and September 2012, we utilized $13,600,000 under the facility by issuing 3,489,860 shares of our common stock to Azimuth at an average price of $3.88 per share, which resulted in $13,393,000 in net proceeds to us. In May 2013, we utilized the remaining $6,400,000 available under the facility by issuing 1,437,481 shares of our common stock to Azimuth at an average price of $4.48 per share, which resulted in $6,347,000 of net proceeds to us. Shares were issued to Azimuth at a discount of 5% to the volume-weighted average price of our common stock over a preceding period of trading days. Shares sold under this facility were sold pursuant to a shelf registration statement declared effective by the SEC on July 3, 2012.