Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Accumulated amortization of intangible assets	$ 15,936	$ 14,676
Common stock, par value (in dollars per share)	$ 0.025	$ 0.025
Common stock, shares authorized	140,000,000	140,000,000
Common stock, shares issued	92,877,209	91,550,851
Common stock, shares outstanding	92,877,209	91,550,851