Stock-based Awards (Details - Options) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Additional disclosure
Stock-based compensation expense	$ 8,972	$ 6,846	$ 18,069	$ 12,753
Options
Number of Options
Outstanding at the beginning of period (in shares)			16,714,216
Granted (in shares)			1,439,287
Exercised (in shares)			(463,426)
Canceled/forfeited (in shares)			(1,002,936)
Outstanding at the end of the period (in shares)	16,687,141		16,687,141		16,714,216
Weighted-Average Exercise Price
Outstanding at the beginning of period (in dollars per share)			$ 12.46
Granted (in dollars per share)			9.60
Exercised (in dollars per share)			6.89
Canceled/forfeited (in dollars per share)			14.03
Outstanding at the end of the period (in dollars per share)	$ 12.28		$ 12.28		$ 12.46
Additional disclosure
Weighted average remaining contractual life (in years)			7 years		7 years 8 months 12 days
Remaining stock-based compensation expense for unvested awards	$ 44,300		$ 44,300
Weighted average period over which remaining stock based compensation expense for unvested awards is expected to be recognized			2 years 9 months
Stock-based compensation expense	$ 3,800	$ 3,700	$ 8,400	$ 7,000