Stockholders' Equity (Tables)

9 Months Ended

Sep. 30, 2015

Changes in Stockholders' Equity

Changes in stockholders’ equity for the nine months ended September 30, 2015 and 2014 were as follows:

	For the Nine Months Ended September 30,
	2015			2014
Balance at December 31, 2014 and 2013	$	143,469		$	152,958
Net loss		(21,982	)		(47,412	)
Stock-based compensation		7,484			4,756
Exercise of stock options		3,473			3,967
Change in unrealized loss on marketable securities		22			(13	)
Issuance of common stock		297,137			—
Issuance of common stock from the exercise of warrants		—			5,251
Issuance of common stock under the Employee Stock Purchase Plan		137			96
Balance at September 30, 2015 and 2014	$	429,740		$	119,603