Basis of Presentation, Organization and Summary of Significant Accounting Policies (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2015

Dec. 31, 2014

Accounting Policies [Abstract]

Composition of Investment Securities

The following table sets forth the composition of the Company’s investment securities (in thousands) as of December 31, 2014:

				Unrealized
As of December 31, 2014	Maturity in Years	Amortized Cost		Gains		Losses			Fair Value
Corporate debt securities	Less than 1 year	$	70,521	$	—	$	(8	)	$	70,513

The following table sets forth the composition of the Company’s investment securities (in thousands):

As of December 31, 2014	Maturity in Years	Amortized Cost		Unrealized					Fair Value
				Gains		Losses
Corporate debt securities	Less than 1 year	$	70,521	$	—	$	(8	)	$	70,513
As of December 31, 2013	Maturity in Years	Amortized Cost		Unrealized					Fair Value
				Gains		Losses
Corporate debt securities	Less than 1 year	$	10,465	$	2	$	—		$	10,467

Potentially Dilutive Securities Not Included in Calculation of Diluted Net Loss Per Share Attributable to Common Stockholders

Potentially dilutive securities not included in the calculation of diluted net loss per share attributable to common stockholders because to do so would be anti-dilutive are as follows (in common stock equivalent shares):

	Nine Months Ended September 30,
	2015		2014
Warrants for common stock		152,735		206,340
Common stock options and restricted stock units		1,527,098		2,527,067
		1,679,833		2,733,407

Potentially dilutive securities not included in the calculation of diluted net loss per share attributable to common stockholders because to do so would be anti-dilutive are as follows (in common stock equivalent shares):

	Years Ended December 31,
	2014		2013
Redeemable convertible preferred stock		—		10,179,372
Convertible preferred stock		—		971,820
Warrants for convertible preferred stock		—		231,821
Warrants for common stock		206,340		702
Common stock options		2,408,634		1,543,667
		2,614,974		12,927,382