Legal Matters	12 Months Ended
Dec. 31, 2011
Legal Matters [Abstract]
Legal Matters	(10) Legal Matters On February 9, 2007, Nuvelo and certain of Nuvelo's former and then current officers and directors were named as defendants in a purported securities class action lawsuit filed in the United States District Court for the Southern District of New York. The suit alleged violations of the Securities Exchange Act of 1934 related to the clinical trial results of alfimeprase, which Nuvelo announced on December 11, 2006, and the suit sought damages on behalf of purchasers of Nuvelo's common stock during the period between January 5, 2006 and December 8, 2006. On December 29, 2010, ARCA and the other defendants reached a settlement of the litigation with the plaintiffs, after participating in mediation, and on February 25, 2011, the parties entered into a settlement agreement. ARCA's insurance carriers funded the settlement. On July 25, 2011 the order for final settlement became effective and the suit was dismissed. On or about December 6, 2001, Variagenics, Inc. was sued in a complaint filed in the United States District Court for the Southern District of New York naming it and certain of its officers and underwriters as defendants. The complaint purportedly was filed on behalf of persons purchasing Variagenics' stock between July 21, 2000 and December 6, 2000, and alleged violations of certain sections of the Securities Act of 1933, as amended, and the Securities Exchange Act of 1934, as amended. The complaint alleged that, in connection with Variagenics' July 21, 2000 initial public offering, or IPO, the defendants failed to disclose additional and excessive commissions purportedly solicited by and paid to the underwriter defendants in exchange for allocating shares of Variagenics' stock to preferred customers and alleged agreements among the underwriter defendants and preferred customers tying the allocation of IPO shares to agreements to make additional aftermarket purchases at predetermined prices. ARCA was involved in this litigation as a result of Nuvelo's merger with Variagenics in January 2003. On April 1, 2009 the parties entered into a settlement agreement. On October 5, 2009, the Court approved the settlement agreement. ARCA's share of the settlement was approximately $385,000 and was funded by ARCA's insurance carrier. Although the settlement was approved by the Court, it had been appealed by members of the class. On January 9, 2012 the appeal was dismissed by the Court and the suit was settled.

(10) Legal Matters

On February 9, 2007, Nuvelo and certain of Nuvelo's former and then current officers and directors were named as defendants in a purported securities class action lawsuit filed in the United States District Court for the Southern District of New York. The suit alleged violations of the Securities Exchange Act of 1934 related to the clinical trial results of alfimeprase, which Nuvelo announced on December 11, 2006, and the suit sought damages on behalf of purchasers of Nuvelo's common stock during the period between January 5, 2006 and December 8, 2006. On December 29, 2010, ARCA and the other defendants reached a settlement of the litigation with the plaintiffs, after participating in mediation, and on February 25, 2011, the parties entered into a settlement agreement. ARCA's insurance carriers funded the settlement. On July 25, 2011 the order for final settlement became effective and the suit was dismissed.

On or about December 6, 2001, Variagenics, Inc. was sued in a complaint filed in the United States District Court for the Southern District of New York naming it and certain of its officers and underwriters as defendants. The complaint purportedly was filed on behalf of persons purchasing Variagenics' stock between July 21, 2000 and December 6, 2000, and alleged violations of certain sections of the Securities Act of 1933, as amended, and the Securities Exchange Act of 1934, as amended. The complaint alleged that, in connection with Variagenics' July 21, 2000 initial public offering, or IPO, the defendants failed to disclose additional and excessive commissions purportedly solicited by and paid to the underwriter defendants in exchange for allocating shares of Variagenics' stock to preferred customers and alleged agreements among the underwriter defendants and preferred customers tying the allocation of IPO shares to agreements to make additional aftermarket purchases at predetermined prices. ARCA was involved in this litigation as a result of Nuvelo's merger with Variagenics in January 2003. On April 1, 2009 the parties entered into a settlement agreement. On October 5, 2009, the Court approved the settlement agreement. ARCA's share of the settlement was approximately $385,000 and was funded by ARCA's insurance carrier. Although the settlement was approved by the Court, it had been appealed by members of the class. On January 9, 2012 the appeal was dismissed by the Court and the suit was settled.