Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Cash and cash equivalents	$ 108,238	$ 160,203
Accounts payable	$ 2,708	$ 7,698
Common stock, par value (USD per share)	$ 0.001	$ 0.001
Common stock, shares authorized	33,333,333	33,333,333
Common stock, shares issued	19,837,109	19,575,150
Common stock, shares outstanding	19,837,109	19,575,150
Viking
Cash and cash equivalents	$ 0	$ 756
Accounts payable	$ 0	$ 2,211