Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Relevant Data Used to Estimate Fair Value of Stock Option Grants

The relevant data used to determine the value of the stock option grants for the three months ended March 31, 2019 and 2018 were as follows:

	Three months ended
	March 31,
	2019		2018
Risk-free interest rates	2.56% - 2.67%		2.72 - 2.74%
Expected dividend yield	0.00%		0.00%
Expected term (in years)		6.0		6.0
Expected volatility	69.3% - 69.5%		71.4 - 71.5%

Summary of Stock Option Activity

The following table summarizes stock option activity for the three months ended March 31, 2019:

(In thousands, except per share amounts)	SharesIssuable UnderOptions			Weighted Average ExercisePrice Per Share
Outstanding as of December 31, 2018		4,435		$	19.21
Granted		638			14.47
Exercised		—			7.15
Cancelled		(92	)		21.85
Outstanding as of March 31, 2019		4,981		$	18.56
Options vested and expected to vest at March 31, 2019		4,981		$	18.56
Options exercisable at March 31, 2019		2,689		$	17.67

Summary of of RSU Activity

The following table summarizes the RSU activity for the three months ended March 31, 2019:

(In thousands, except per share amounts)	Number of Shares			Weighted Average Grant Date Fair Value Per Share
Nonvested balance as of December 31, 2018		252		$	22.25
Granted		771			14.75
Vested/Released		(46	)		22.31
Cancelled		(3	)		20.89
Nonvested Balance as of March 31, 2019		974		$	16.31

Stock-Based Compensation Expense Related to Stock Options, and RSUs and Shares Purchased Under Employee Stock Purchase Plan

The Company recorded stock-based compensation expense related to stock options and RSUs and shares purchased under the Employee Stock Purchase Plan for the three months ended March 31, 2019 and 2018 as follows:

	For the three months ended March 31,
(In thousands)	2019		2018
Research and development	$	1,156	$	1,150
Selling, general and administrative		2,697		2,507
Total	$	3,853	$	3,657