Stock-based Awards (Details - Options) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Additional disclosure
Stock-based compensation expense	$ 10,247	$ 9,908	$ 28,316	$ 22,661
Options
Number of Options
Outstanding at the beginning of period (in shares)			16,714,216
Granted (in shares)			1,492,481
Exercised (in shares)			(2,126,522)
Canceled/forfeited (in shares)			(1,516,635)
Outstanding at the end of the period (in shares)	14,563,540		14,563,540		16,714,216
Weighted-Average Exercise Price
Outstanding at the beginning of period (in dollars per share)			$ 12.46
Granted (in dollars per share)			9.69
Exercised (in dollars per share)			9.12
Canceled/forfeited (in dollars per share)			14.45
Outstanding at the end of the period (in dollars per share)	$ 12.46		$ 12.46		$ 12.46
Additional disclosure
Weighted average remaining contractual life (in years)			7 years 4 months 24 days		7 years 8 months 12 days
Remaining stock-based compensation expense for unvested awards	$ 38,600		$ 38,600
Weighted average period over which remaining stock based compensation expense for unvested awards is expected to be recognized			2 years 6 months 18 days
Stock-based compensation expense	$ 4,200	$ 5,300	$ 12,600	$ 12,300