CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) Non-Cash Activities (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Other Significant Noncash Transactions [Line Items]
Unrealized loss (gain) on available-for-sale securities	$ 30	$ (19)
Common stock issued to Board of Directors and Scientific Advisory Board that was earned and accrued for in a previous period
Other Significant Noncash Transactions [Line Items]
Other significant noncash transactions	323	300
Common stock issued to employees that was earned and accrued for in a previous period
Other Significant Noncash Transactions [Line Items]
Other significant noncash transactions	746	282
Net change in accounts payable and accrued expenses related to purchases of property and equipment
Other Significant Noncash Transactions [Line Items]
Other significant noncash transactions	$ (252)	$ 184