Equity Plan - Stock Option Activity (Details) - Options	9 Months Ended
	Sep. 30, 2016 USD ($) $ / shares shares
Number of Shares
Outstanding at the beginning of the period (in shares)	1,775,027
Granted (in shares)	300,500
Exercised (in shares)	(118,885)
Forfeited or expired (in shares)	(184,520)
Outstanding at the end of the period (in shares)	1,772,122
Vested or expected to vest (in shares)	1,683,516
Exercisable at the end of the period (in shares)	1,199,679
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share) | $ / shares	$ 10.62
Granted (in dollars per share) | $ / shares	10.36
Exercised (in dollars per share) | $ / shares	6.49
Forfeited or expired (in dollars per share) | $ / shares	20.08
Outstanding at the end of the period (in dollars per share) | $ / shares	$ 9.86
Additional Information
Weighted Average Remaining Contractual Life - Outstanding at the end of the period (in years)	6 years 1 month 6 days
Weighted Average Remaining Contractual Life - Vested or expected to vest (in years)	6 years 1 month 6 days
Weighted Average Remaining Contractual Life - Exercisable at the end of the period (in years)	4 years 10 months 24 days
Aggregate Intrinsic Value - Outstanding at the end of the period (in dollars) | $	$ 4,560,918
Aggregate Intrinsic Value - Vested or expected to vest (in dollars) | $	4,332,872
Aggregate Intrinsic Value - Exercisable at the end of the period (in dollars) | $	$ 3,691,857