Condensed Consolidated Balance Sheets (parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position
Accounts receivable, allowance for doubtful accounts	$ 0	$ 0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	49,092,260	47,614,150
Common stock, shares outstanding	49,092,260	47,614,150