Major Customers, Partnerships and Strategic Alliances (Details Textual) (USD $)	3 Months Ended		6 Months Ended			1 Months Ended	6 Months Ended	3 Months Ended		6 Months Ended				6 Months Ended		3 Months Ended	6 Months Ended	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended	6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011	Oct. 31, 2009 California Institute for Regenerative Medicine [Member]	Jun. 30, 2012 California Institute for Regenerative Medicine [Member]	Jun. 30, 2012 CHDI Foundation, Inc. [Member]	Jun. 30, 2011 CHDI Foundation, Inc. [Member]	Jun. 30, 2012 CHDI Foundation, Inc. [Member]	Jun. 30, 2011 CHDI Foundation, Inc. [Member]	Jul. 31, 2012 CHDI Foundation, Inc. [Member]	Mar. 08, 2012 CHDI Foundation, Inc. [Member]	Jun. 30, 2012 Michael J. Fox Foundation for Parkinson's Research [Member]	Jun. 30, 2012 Juvenile Diabetes Research Foundation International [Member]	Jun. 30, 2012 Shire AG [Member]	Jun. 30, 2012 Shire AG [Member] Target	Jun. 30, 2012 Sigma-Aldrich Corporation [Member]	Jun. 30, 2011 Sigma-Aldrich Corporation [Member]	Jun. 30, 2012 Sigma-Aldrich Corporation [Member]	Jun. 30, 2011 Sigma-Aldrich Corporation [Member]	Jun. 30, 2012 Dow AgroSciences [Member]	Jun. 30, 2011 Dow AgroSciences [Member]	Jun. 30, 2012 Dow AgroSciences [Member]	Jun. 30, 2011 Dow AgroSciences [Member]	Jun. 30, 2012 Commercial milestones [Member]	Jun. 30, 2012 Commercial milestones [Member]	Jun. 30, 2012 License agreement terms [Member]	Jun. 30, 2012 License agreement terms [Member] California Institute for Regenerative Medicine [Member]	Jun. 30, 2011 License agreement terms [Member] California Institute for Regenerative Medicine [Member]	Jun. 30, 2012 License agreement terms [Member] California Institute for Regenerative Medicine [Member]	Jun. 30, 2011 License agreement terms [Member] California Institute for Regenerative Medicine [Member]	Jun. 30, 2012 License agreement terms [Member] Michael J. Fox Foundation for Parkinson's Research [Member]	Jun. 30, 2011 License agreement terms [Member] Michael J. Fox Foundation for Parkinson's Research [Member]	Jun. 30, 2012 License agreement terms [Member] Michael J. Fox Foundation for Parkinson's Research [Member]	Jun. 30, 2011 License agreement terms [Member] Michael J. Fox Foundation for Parkinson's Research [Member]	Jun. 30, 2012 License agreement terms [Member] Juvenile Diabetes Research Foundation International [Member]	Jun. 30, 2011 License agreement terms [Member] Juvenile Diabetes Research Foundation International [Member]	Jun. 30, 2012 License agreement terms [Member] Juvenile Diabetes Research Foundation International [Member]	Jun. 30, 2011 License agreement terms [Member] Juvenile Diabetes Research Foundation International [Member]	Jun. 30, 2012 License agreement terms [Member] Shire AG [Member]	Jun. 30, 2012 License agreement terms [Member] Sigma-Aldrich Corporation [Member]	Jun. 30, 2011 License agreement terms [Member] Sigma-Aldrich Corporation [Member]	Jun. 30, 2012 License agreement terms [Member] Sigma-Aldrich Corporation [Member]	Jun. 30, 2011 License agreement terms [Member] Sigma-Aldrich Corporation [Member]	Jun. 30, 2012 Additional Funding Agreement Terms [Member] Michael J. Fox Foundation for Parkinson's Research [Member]	Jun. 30, 2012 Additional Funding Agreement Terms [Member] Juvenile Diabetes Research Foundation International [Member]	Jun. 30, 2012 Upfront license fee [Member] Shire AG [Member]	Jun. 30, 2012 Maximum [Member]	Jun. 30, 2012 Minimum [Member]
Major Customers, Partnerships and Strategic Alliances (Textual) [Abstract]
Number of gene targets																	7
Number of initial gene targets																	4
Number of additional gene targets																	2
Research program to develop laboratory research reagents																	6 years			3 years				3 years
IND or CTA submission amount	$ 7,574,000	$ 8,119,000	$ 14,857,000	$ 16,381,000													$ 8,500,000
Deferred revenue	2,208,000		2,208,000		17,000																																											12,100,000
Royalty revenues																	0	306,000	139,000	607,000	431,000			2,300,000				4,000,000
Revenue attributable to research and development								400,000	400,000	800,000	400,000							1,000,000		1,000,000	671,000	400,000	500,000	900,000	1,000,000								0	100,000	0	400,000												13,000,000
Revenue related to commercial milestone																		1,306,000	139,000	1,607,000	1,102,000					1,000,000	1,000,000
Minimum Sublicense Annual Fees Specific Reckoning Period			11 years
Annual fees																																																	3,000,000	250,000
Fee due			25,300,000
Research grants	762,000	906,000	2,341,000	1,619,000
Funds due under the agreement with MJFF						14,500,000																																								1,000,000
Revenues under the agreement																													300,000	400,000	600,000	800,000					0	0	800,000	0
Grant funding amount maximum under amended agreement.																																															3,000,000
Related costs and expenses								400,000	400,000	800,000	400,000					1,200,000	1,700,000					100,000	500,000	300,000	700,000				300,000	600,000	600,000	1,000,000										100,000	200,000	200,000	300,000
Agreement date							2009-10			2011-04				2007-01	2006-10
Potential funding																																																	2,100,000	1,800,000
Upfront cash payment received under collaboration agreement																				20,000,000
Expected amount to be received for research and development							5,200,000																																		213,500,000
One-time commercial license fee																						6,000,000		6,000,000																		5,000,000		5,000,000
Percentage of royalties to be received from sublicensing																								25.00%
Reduced royalty rate																				10.50%
Funding available under the amended agreement															2,800,000			25,000,000		25,000,000
Funding received from research grant.																																														900,000
Funds Due Under Agreement												1,800,000	1,300,000
Agreement to receive							4 years			1 year				2 years
Final Agreement Amount Received															800,000
Common stock																				636,133
Common stock, valued																				4,900,000
Upfront license fee																				$ 15,100,000