Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

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 years ended December 31, 2017, 2016 and 2015 is as follows:

	December 31,
	2017		2016		2015
Risk-free interest rates	1.97%-2.29%		0.74-1.75%		1.49-1.92%
Expected dividend yield	0.00%		0.00%		0.00%
Expected term (in years)		6.0		5.6		6.0
Expected volatility	69.9%-72.8%		67.3-99.9%		76.4-83.9%

Summary of Stock Option Activity

The following table summarizes stock option activity for the year ended December 31, 2017:

(In thousands, except per share amounts)	SharesIssuable UnderOptions			WeightedAverage ExercisePrice
Outstanding as of December 31, 2016		3,079		$	14.84
Granted		1,448			22.29
Exercised		(308	)		12.25
Cancelled		(419	)		22.78
Outstanding as of December 31, 2017		3,800		$	17.75
Options vested and expected to vest at December 31, 2017		3,800		$	17.75
Options exercisable at December 31, 2017		1,689		$	14.99

Summary of of RSU Activity

Restricted Stock Units

On January 4, 2016, the Company granted 189,300 RSUs with performance and time-based vesting conditions to certain executives. These RSUs vest, and the underlying shares of common stock become deliverable, beginning when ZILRETTA is approved (the “Milestone”). The number of shares that vest varies based on the timing of achieving the Milestone. As a result of the Milestone being achieved on October 6, 2017, the number of shares of the Company’s common stock earned under these awards is 122,800, subject to ongoing employment with the Company for a period of 2 years. The 122,800 shares had an approximate value of $2.2 million as of the original grant date of which $1.6 million was recognized in the fourth quarter of 2017 upon achieving the milestone and the remaining $0.6 million will be recognized over a period of two years.

The following table summarizes the RSU activity for the year ended December 31, 2017:

(In thousands, except per share amounts)	Number of Shares			WeightedAverage Grant Date Fair Value
Nonvested as of December 31, 2016		189		$	15.77
Granted		—			—
Cancelled		(66	)		—
Vested/Released		(41	)		16.43
Nonvested as of December 31, 2017		82		$	16.43

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

The Company recorded stock-based compensation expense related to stock options, restricted stock and shares purchased under the employee stock purchase plan for the years ended December 31, 2017, 2016 and 2015 as follows:

	Year Ended December 31,
(In thousands)	2017		2016		2015
Research and development	$	3,979	$	2,341	$	1,412
Selling, general and administrative		7,563		4,429		3,171
	$	11,542	$	6,770	$	4,583