XML 75 R32.htm IDEA: XBRL DOCUMENT

Redeemable Convertible Preferred Stock and Equity (Deficit) (Tables)

12 Months Ended

Dec. 31, 2015

Redeemable Convertible Preferred Stock And Equity Deficit [Abstract]

Summary of Common Stock Reserved for Future Issuance

Shares of Common Stock outstanding, shares of stock plans outstanding and shares reserved for future issuance related to stock options and RSUs grant and Employee Stock Purchase Plan (“ESPP”) purchases are as follows (in thousands):

	December 31,
	2015		2014
Common stock outstanding		61,985		59,046
Stock options outstanding		13,583		14,427
RSUs outstanding		865		560
Common stock warrants outstanding		7		173
Shares reserved for future stock options and RSUs grant		3,394		5,358
Shares reserved for future ESPP offering		1,285		1,600
Total shares of common stock reserved		81,119		81,164

Summary of Stock Option Transactions

Stock option transactions, including forfeited options granted under the 2014 Plan as well as prior plans, are summarized below:

	Shares (In thousands)			Weighted Average Exercise per Share		Weighted Average Remaining Contractual Life (In Years)		Aggregate Intrinsic Value (In thousands)
Outstanding at December 31, 2014		14,427		$	7.10
Granted		1,891			27.27
Exercised		(2,362	)		4.28
Expired		(29	)		3.68
Forfeited		(344	)		18.08
Outstanding at December 31, 2015		13,583			10.12		6.07	$	276,401
Vested and expected to vest, December 31, 2015		13,321			9.84		6.01		274,820
Exercisable at December 31, 2015		10,029		$	6.13		5.11	$	244,134

Summary of Restricted Stock Unit Activity

The following table summarizes restricted stock unit activity:

	Number of Shares			Fair Value at Grant
Unvested at December 31, 2014		559,582		$	18.00
Granted		586,008			29.66
Vested		(241,497	)		18.00
Forfeited		(39,244	)		25.08
Unvested at December 31, 2015		864,849		$	25.58

Schedule of Allocated Stock-Based Compensation Expense

Stock-based compensation related to options granted is allocated to research and development and general and administrative expense for the years ended December 31, 2015, 2014, and 2013 was as follows (in thousands):

	Years Ended December 31,
	2015		2014		2013
Research and development	$	16,987	$	10,893	$	1,925
General and administrative		10,694		7,805		1,519
Total stock-based compensation expense	$	27,681	$	18,698	$	3,444

Schedule of Assumptions used to Estimate Fair Value of Stock Options Granted and Employee Stock Purchase Plans

The assumptions used to estimate the fair value of stock options granted and ESPPs using the Black-Scholes option valuation model were as follows:

	Years Ended December 31,
	2015			2014			2013
Stock Options
Expected term (in years)		5.2			5.1			4.1
Expected volatility		69.9	%		62.8	%		71.6	%
Risk-free interest rate		1.7	%		1.7	%		0.8	%
Expected dividend yield		—			—			—
Weighted average estimated fair value	$	16.12		$	9.51		$	6.19

ESPPs
Expected term (in years)	1.1 - 1.3				1.2			—
Expected volatility	64.8 - 65.3%			61.7 - 65.5%				—	%
Risk-free interest rate		0.3	%	0.1 - 0.4%				—	%
Expected dividend yield		—			—			—
Weighted average estimated fair value	$	10.54		$	13.22		$	—

Schedule of Warrants to Purchase Shares of Common Stock

The following warrants to purchase shares of Common Stock were issued in connection with certain facility and equipment lease financing arrangements and are outstanding at December 31, 2015:

Year of Issuance	Number of Shares		Exercise Price per Share		Reason for Issuance	Expiration Date
1996		1,600	$	4.38	Issued in connection with lease agreement	Five years after initial public offering or upon merger or sale of the Company’s assets, whichever occurs first
2000		5,538	$	15.00	Issued in connection with lease agreement	Five years after initial public offering or upon merger or sale of the Company’s assets, whichever occurs first
		7,138

- Definition

Tabular disclosure of warrants or rights issued. Warrants and rights outstanding are derivative securities that give the holder the right to purchase securities (usually equity) from the issuer at a specific price within a certain time frame. Warrants are often included in a new debt issue to entice investors by a higher return potential. The main difference between warrants and call options is that warrants are issued and guaranteed by the company, whereas options are exchange instruments and are not issued by the company. Also, the lifetime of a warrant is often measured in years, while the lifetime of a typical option is measured in months. Disclose the title of issue of securities called for by warrants and rights outstanding, the aggregate amount of securities called for by warrants and rights outstanding, the date from which the warrants or rights are exercisable, and the price at which the warrant or right is exercisable.

+ References + Details