Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2016

Schedule of collaboration revenue components

Below is a summary of the components of the Company's collaboration revenue for the years ended December 2016, 2015 and 2014:



	Years ended December 31,
	2016		2015		2014
License revenue	$	22,937	$	38,083	$	38,373
Research and development activity revenue	9,741		8,378		2,000
API transfer revenue	18,212		5,020		883
Joint operating committee revenue	19		24		3
Total collaboration revenue	$	50,909	$	51,505	$	41,259

Schedule of weighted-average assumptions used to estimate grant date fair value of stock options

The weighted-average assumptions used to estimate grant date fair value of stock options using the Black-Scholes option pricing model were as follows for the years ended December 31, 2016, 2015 and 2014:



	Years ended December 31,
	2016	2015	2014
Expected common stock price volatility	71%	72%	82%
Risk-free interest rate	1.14% - 2.37%	1.35% - 2.24%	1.61% - 2.13%
Expected term of options (years)	6.1	6.2	6.2
Expected dividend yield	—	—	—

Schedule of share-based compensation expense

Share-based compensation expense includes expenses related to stock options and RSUs granted to employees, non-employee directors and consultants, as well as the option granted to employees to purchase shares under the ESPP, all of which have been reported in the Company’s Statements of Operations as follows:



	Years ended December 31,
	2016		2015		2014
Research and development	$	21,380	$	16,608	$	7,594
General and administrative	10,280		8,152		5,446
Total	$	31,660	$	24,760	$	13,040