ORGANIZATION, BASIS OF PRESENTATION, AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - (Tables)

3 Months Ended

Mar. 31, 2021

Accounting Policies [Abstract]

Schedule of Revenue from Strategic Partnering Collaboration Agreements and Research Activity Grants as a Percentage of Total Revenues

Revenues from major collaboration agreements and research activity grants as a percentage of total revenues were as follows:

	Three Months Ended March 31,
	2021		2020
Biogen MA, Inc.	40	%	—
Novartis Institutes for BioMedical Research, Inc.	30	%	—
Kite Pharma, Inc.	24	%	55	%
Sanofi Genzyme	4	%	4	%
Pfizer Inc.	—		27	%

Schedule of Cash and Cash Equivalents

A reconciliation of cash, cash equivalents and restricted cash reported within the Condensed Consolidated Balance Sheets to the amounts reported within the accompanying Condensed Consolidated Statements of Cash Flows was as follows (in thousands):

	March 31, 2021		December 31, 2020		March 31, 2020		December 31, 2019
Cash and cash equivalents	$	122,975	$	131,329	$	85,749	$	80,428
Non-current restricted cash	1,500		1,500		1,500		1,500
Cash, cash equivalents and restricted cash as reported within the accompanying Condensed Consolidated Statements of Cash Flows	$	124,475	$	132,829	$	87,249	$	81,928

Restrictions on Cash and Cash Equivalents

A reconciliation of cash, cash equivalents and restricted cash reported within the Condensed Consolidated Balance Sheets to the amounts reported within the accompanying Condensed Consolidated Statements of Cash Flows was as follows (in thousands):

	March 31, 2021		December 31, 2020		March 31, 2020		December 31, 2019
Cash and cash equivalents	$	122,975	$	131,329	$	85,749	$	80,428
Non-current restricted cash	1,500		1,500		1,500		1,500
Cash, cash equivalents and restricted cash as reported within the accompanying Condensed Consolidated Statements of Cash Flows	$	124,475	$	132,829	$	87,249	$	81,928