Equity Incentive Plans and Stock-Based Compensation (Details 2) - Options - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Number of Shares
Outstanding, at the beginning of the period (in shares)			3,235,891
Options granted (in shares)	40,000	100,000	40,000	700,000
Options exercised (in shares)			(1,087,931)
Options forfeited (in shares)			(391,542)
Outstanding, at the end of the period (in shares)	1,796,418		1,796,418
Vested or expected to vest at the end of the period (in shares)	1,782,725		1,782,725
Options exercisable at the end of the period (in shares)	1,437,761		1,437,761
Weighted Average Exercise Price
Outstanding at the beginning of the year (in dollars per shares)			$ 10.25
Options granted (in dollars per share)			12.57
Options exercised (in dollars per share)			7.68
Options forfeited (in dollars per share)			13.86
Outstanding at the end of the period (in dollars per shares)	$ 11.07		11.07
Vested or expected to vest at the end of the period (in dollars per share)	11.06		11.06
Options exercisable at the end of the period (in dollars per share)	$ 10.68		$ 10.68
Weighted Average Remaining Contractual Term
Outstanding			4 years 5 months 26 days
Vested or expected to vest			4 years 5 months 15 days
Options exercisable			3 years 8 months 26 days
Aggregate Intrinsic Value
Outstanding	$ 4,499		$ 4,499
Vested or expected to vest	4,492		4,492
Options exercisable	4,312		4,312
Share Based Compensation Arrangement by Share Based Payment Award Options, Grants in Period, Total Fair Value	$ 200	$ 400	$ 200	$ 3,000