Summary of Significant Accounting Policies (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Summary of stock based compensation expense included in statements of operations
Total stock-based compensation expense included in loss from operations	$ 1,881	$ 2,296	$ 4,752	$ 4,570
Cost of product sales [Member]
Summary of stock based compensation expense included in statements of operations
Total stock-based compensation expense included in loss from operations	78	76	187	132
Research and development [Member]
Summary of stock based compensation expense included in statements of operations
Total stock-based compensation expense included in loss from operations	350	613	886	1,221
Selling, general and administrative [Member]
Summary of stock based compensation expense included in statements of operations
Total stock-based compensation expense included in loss from operations	$ 1,453	$ 1,607	$ 3,679	$ 3,217