FAIR VALUE MEASUREMENTS - (Tables)

3 Months Ended

Mar. 31, 2020

Fair Value Disclosures [Abstract]

Summary of Fair Value Measurements of Cash Equivalents, Available-for-Sale Marketable Securities and Free Share Asset/Liability

The fair value measurements of the Company’s cash equivalents, available-for-sale marketable securities and the free shares asset are identified at the following levels within the fair value hierarchy (in thousands):

	March 31, 2020
	Fair Value Measurements
	Total		Level 1		Level 2		Level 3
Assets:
Cash equivalents:
Money market funds	$	59,609	$	59,609	$	—	$	—
Total	59,609		59,609		—		—
Marketable securities:
Commercial paper securities	130,179		—		130,179		—
Corporate debt securities	95,518		—		95,518		—
U.S. government-sponsored entity debt securities	51,684		—		51,684		—
Total	277,381		—		277,381		—
Total cash equivalents and marketable securities	$	336,990	$	59,609	$	277,381	$	—
Free shares asset	$	163	$	—	$	—	$	163

	December 31, 2019
	Fair Value Measurements
	Total		Level 1		Level 2		Level 3
Assets:
Cash equivalents:
Money market funds	$	30,496	$	30,496	$	—	$	—
Commercial paper securities	2,999		—		2,999		—
Total	33,495		30,496		2,999		—
Marketable securities:
Commercial paper securities	155,368		—		155,368		—
Corporate debt securities	95,017		—		95,017		—
U.S. government-sponsored entity debt securities	53,493		—		53,493		—
Total	303,878		—		303,878		—
Total cash equivalents and marketable securities	$	337,373	$	30,496	$	306,877	$	—
Free shares asset	$	236	$	—	$	—	$	236

Summary of Estimated Fair Value of Free Shares Valuation Assumptions

Free Shares valuation assumptions:	March 31, 2020		December 31, 2019
Sangamo Stock Price (USD)	$	6.66	$	8.68
Sangamo France Stock Price (EUR)	€	1.64	€	2.14
EUR / USD Exchange Rate	0.94		0.91
Estimated Correlation Sangamo and Sangamo France Stock Prices	100.0%		100.0%
Sangamo Stock Price (USD) Volatility Estimate	76.7%		72.5%
Sangamo France Stock Price (EUR) Volatility Estimate	76.7%		72.5%
EUR / USD Exchange Rate Volatility Estimate	6.4%		6.6%
Risk Free Rate and Cost of Debt by Expected Exercise Date	Varies		Varies