Registered Direct Offering	9 Months Ended
Sep. 30, 2012
Registered Direct Offering [Abstract]
Registered Direct Offering	(7) *Registered Direct Offering* On August 2, 2012 the Company entered into a placement agency agreement with Ladenburg Thalmann & Co., Inc (the Placement Agent), pursuant to which the Placement Agent agreed to arrange for the sale of up to 2,436,599 shares of the Company’s common stock in a registered direct public offering (the “Offering”). The Company paid the Placement Agent an aggregate fee equal to 6.5% of the gross proceeds received in the Offering and reimbursed the Placement Agent for certain expenses incurred in connection with the Offering, with a maximum expense reimbursement that when aggregated with the 6.5% fee does not exceed the lesser of (i) 8% of the gross proceeds received by ARCA in the Registered Direct Offering or (ii) $15,000. On August 2, 2012, ARCA entered into separate subscription agreements (the “Subscription Agreements”) with certain institutional investors (the “Investors”) in connection with the Offering, pursuant to which ARCA agreed to sell an aggregate of 2,436,599 shares of its common stock and warrants to purchase a total of 1,827,449 shares of its common stock to the Investor for aggregate gross proceeds of $953,000, before deducting fees to the Placement Agent and other estimated offering expenses payable by the Company. The net proceeds to the Company were $741,000 and the Offering closed on August 8, 2012. The common stock and warrants were sold in combination, consisting of one share of common stock and a warrant to purchase 0.75 shares of common stock. The purchase price per share (with its related warrant) was $0.391. Subject to certain ownership limitations, the warrants are exercisable on the date that is six months after the warrants were issued and will remain exercisable for six years thereafter at an exercise price of $0.46 per share. 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.

Registered Direct Offering

9 Months Ended

Sep. 30, 2012

Registered Direct Offering [Abstract]

(7) Registered Direct Offering

On August 2, 2012 the Company entered into a placement agency agreement with Ladenburg Thalmann & Co., Inc (the Placement Agent), pursuant to which the Placement Agent agreed to arrange for the sale of up to 2,436,599 shares of the Company’s common stock in a registered direct public offering (the “Offering”). The Company paid the Placement Agent an aggregate fee equal to 6.5% of the gross proceeds received in the Offering and reimbursed the Placement Agent for certain expenses incurred in connection with the Offering, with a maximum expense reimbursement that when aggregated with the 6.5% fee does not exceed the lesser of (i) 8% of the gross proceeds received by ARCA in the Registered Direct Offering or (ii) $15,000.

On August 2, 2012, ARCA entered into separate subscription agreements (the “Subscription Agreements”) with certain institutional investors (the “Investors”) in connection with the Offering, pursuant to which ARCA agreed to sell an aggregate of 2,436,599 shares of its common stock and warrants to purchase a total of 1,827,449 shares of its common stock to the Investor for aggregate gross proceeds of $953,000, before deducting fees to the Placement Agent and other estimated offering expenses payable by the Company. The net proceeds to the Company were $741,000 and the Offering closed on August 8, 2012.

The common stock and warrants were sold in combination, consisting of one share of common stock and a warrant to purchase 0.75 shares of common stock. The purchase price per share (with its related warrant) was $0.391. Subject to certain ownership limitations, the warrants are exercisable on the date that is six months after the warrants were issued and will remain exercisable for six years thereafter at an exercise price of $0.46 per share. 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.