Equity Incentive Plans (Stock Option Activity) (Details)	3 Months Ended
	Mar. 31, 2020 USD ($) $ / shares shares
Shares Underlying Stock Options
Outstanding beginning balance, Shares underlying stock options and restricted stock awards (in shares) | shares	5,616,840
Granted, Shares underlying stock options and restricted stock awards (in shares) | shares	675,007
Exercised, Shares underlying stock options and restricted stock awards (in shares) | shares	44,258
Forfeited, Shares underlying stock options and restricted stock awards (in shares) | shares	(1,395,352)
Outstanding ending balance, Shares underlying stock options and restricted stock awards (in shares) | shares	4,852,237
Weighted- Average Exercise Price per Share
Outstanding beginning balance, Weighted - average exercise price (usd per share) | $ / shares	$ 19.5
Granted, Weighted - average exercise price (usd per share) | $ / shares	5.35
Exercised, Weighted - average exercise price (usd per share) | $ / shares	6.89
Forfeited, Weighted - average exercise price (usd per share) | $ / shares	21.17
Outstanding ending balance, Weighted - average exercise price (usd per share) | $ / shares	$ 17.17
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	6 years 5 months 26 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value | $	$ 34,649
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Shares | shares	2,838,302
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price | $ / shares	$ 21.19
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	4 years 9 months 10 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value | $	$ 0