Subsequent Event	9 Months Ended
Sep. 30, 2012
Subsequent Event [Abstract]
Subsequent Event	(10) Subsequent Event *Private Investment in Public Equity* On October 22, 2012, the Company entered into a Subscription Agreement (the “Purchase Agreement”) with certain executive officers, affiliates and directors of the Company in connection with a private placement of its common stock and warrants. Pursuant to the Purchase Agreement, the Company sold an aggregate of 825,184 shares of its common stock and warrants to purchase up to an additional 618,887 shares of its common stock at a total purchase price of $0.39385 per unit, each unit consisting of a share of common stock and a warrant to purchase 0.75 shares of common stock. The Company received gross proceeds of $325,000 before deducting expenses payable by the Company in connection with the transaction. The net proceeds were approximately $280,000 and the transaction closed on October 25, 2012. Additional costs will be incurred to prepare and file the requisite registration statement for the resale of the shares of common stock issued and the shares of common stock underlying the warrants. The warrants issued pursuant to the Purchase Agreement (the “Warrants”) are exercisable until October 25, 2017 and have an exercise price of $0.3001 per share, equal to the closing sales price of ARCA’s common stock on the NASDAQ Capital Market on October 22, 2012. The exercise price of the warrants is subject to adjustment in the case of stock splits, stock dividends, combinations of shares and similar recapitalization transactions.

Subsequent Event

9 Months Ended

Sep. 30, 2012

(10) Subsequent Event

Private Investment in Public Equity

On October 22, 2012, the Company entered into a Subscription Agreement (the “Purchase Agreement”) with certain executive officers, affiliates and directors of the Company in connection with a private placement of its common stock and warrants. Pursuant to the Purchase Agreement, the Company sold an aggregate of 825,184 shares of its common stock and warrants to purchase up to an additional 618,887 shares of its common stock at a total purchase price of $0.39385 per unit, each unit consisting of a share of common stock and a warrant to purchase 0.75 shares of common stock. The Company received gross proceeds of $325,000 before deducting expenses payable by the Company in connection with the transaction. The net proceeds were approximately $280,000 and the transaction closed on October 25, 2012. Additional costs will be incurred to prepare and file the requisite registration statement for the resale of the shares of common stock issued and the shares of common stock underlying the warrants.

The warrants issued pursuant to the Purchase Agreement (the “Warrants”) are exercisable until October 25, 2017 and have an exercise price of $0.3001 per share, equal to the closing sales price of ARCA’s common stock on the NASDAQ Capital Market on October 22, 2012. The exercise price of the warrants is subject to adjustment in the case of stock splits, stock dividends, combinations of shares and similar recapitalization transactions.