Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2014

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment [Table Text Block]

Property and equipment consisted of the following:

	Estimated Useful Lives		December 31,
			2013			2014
Laboratory equipment		7	$	4,796,393		$	5,828,045
Office equipment and software		3 – 7		972,789			1,225,298
Leasehold improvements		7		348,901			400,018
Assets not in service				503,208			23,836
				6,621,291			7,477,197
Less accumulated depreciation				(2,781,865	)		(3,506,532	)
			$	3,839,426		$	3,970,665