Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2016

Summarized Financial Information of Equity Method Investments

Summarized financial data as of December 31, 2016 and 2015, and for the years ended December 31, 2016, 2015, and 2014, for the Company's equity method investments for which separate financial statements are not included, pursuant to SEC Regulation S-X Article 3-09, are shown in the following tables.



	December 31,
	2016		2015
Current assets	$	77,761	$	28,123
Non-current assets	11,040		1,539
Total assets	88,801		29,662
Current liabilities	11,588		6,274
Net assets	$	77,213	$	23,388



	Year Ended December 31,
	2016			2015			2014
Revenues, net	$	417		$	1,176		$	940
Operating expenses	62,373			32,513			17,289
Operating loss	(61,956		)	(31,337		)	(16,349		)
Other, net	1,535			(64		)	35
Net loss	$	(60,421	)	$	(31,401	)	$	(16,314	)

Rollforward of Allowance for Doubtful Receivable Accounts

The following table shows the activity in the allowance for doubtful receivable accounts for the years ended December 31, 2016 and 2015:



	2016			2015
Beginning balance	$	2,081		$	565
Charged to operating expenses	1,963			1,757
Write offs of accounts receivable	(341		)	(241		)
Ending balance	$	3,703		$	2,081

Estimated Useful Lives of Property, Plant and Equipment

The estimated useful lives of these assets are as follows:



	Years
Land improvements	4–20
Buildings and building improvements	3–25
Furniture and fixtures	1–10
Equipment	1–10
Breeding stock	1–4
Computer hardware and software	1–7

Leasehold improvements are amortized over the shorter of the useful life of the asset or the applicable lease term, generally one to twenty years.

Summary of Assumptions Used in Option Pricing Model

The assumptions used in the Black-Scholes option pricing model for the years ended December 31, 2016, 2015 and 2014 are set forth in the table below:



	2016	2015	2014
Valuation assumptions
Expected dividend yield	0%	0%	0%
Expected volatility	59%—60%	59%—62%	62%—64%
Expected term (years)	6.25	6.25	6.25
Risk-free interest rate	1.23%—2.17%	1.56%—1.95%	1.82%—2.14%