Stockholders' Equity And Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2019

Stockholders' Equity [Line Items]

Summary Of Stock Option Activity

	Stock Options Outstanding
			Weighted
	Number		average
	of shares		exercise price
Balances — December 31, 2018	2,956,687	$	17.04
Options granted	174,303
Options exercised	(98,928)
Options canceled	(9,667)
Options expired	(150,625)
Balances — March 31, 2019	2,871,770	$	17.22
Exercisable — March 31, 2019	1,446,422	$	16.06

Schedule Of Fair Value Of Employee Stock Options

	Three-Month Periods Ended March 31,
	2019	2018
Expected term in years	0.4 - 6.1	6.1
Expected volatility	70%	70%
Risk-free interest rate	2.4 - 2.7%	2.7%
Dividend yield	—	—

Summary Of Stock-Based Compensation Expense

	Three-Month Periods Ended
	March 31,
	2019		2018
General and administrative	$	1,485	$	2,699
Research and development		876		721
Total stock-based compensation expense	$	2,361	$	3,420

2017 Employee Stock Purchase Plan [Member]

Stockholders' Equity [Line Items]

Schedule Of Fair Value Of Employee Stock Options

	Three-Month Periods Ended March 31,
	2019	2018
Expected term in years	0.5 - 1.0	0.5 - 1.0
Expected volatility	70%	70%
Risk-free interest rate	2.5% - 2.6%	1.9% - 2.1%
Dividend yield	—	—