CASH AND CASH EQUIVALENTS (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Jun. 30, 2011	Apr. 30, 2011
Cash and cash equivalents
Cash and cash equivalents	$ 57,991	$ 35,073	$ 22,173	$ 21,637	$ 30,222
U.S. dollars
Cash and cash equivalents
Cash and cash equivalents	43,938		12,837
Canadian dollars
Cash and cash equivalents
Cash and cash equivalents	6,974		4,884
Swiss francs
Cash and cash equivalents
Cash and cash equivalents	127		307
Euros
Cash and cash equivalents
Cash and cash equivalents	1,158		1,515
Danish kroner
Cash and cash equivalents
Cash and cash equivalents	2,609		940
Other
Cash and cash equivalents
Cash and cash equivalents	$ 3,185		$ 1,690