Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2018

Schedule of Estimated Stock-Based Compensation Expense

Stock-based compensation expense, net of estimated forfeitures, is reflected in the condensed consolidated statements of operations and comprehensive loss as follows (in thousands):

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2018		2017		2018		2017
Operating Expenses
Research and development	$	877	$	1,501	$	1,759	$	2,982
General and administrative		1,278		2,157		3,217		4,540
Total	$	2,155	$	3,658	$	4,976	$	7,522

Reconciliation of Captions in Consolidated Balance Sheet to Consolidated Statements of Cash Flows

The following is a reconciliation of the captions in the consolidated balance sheet to the consolidated statements of cash flows (in thousands):

	As of
	June 30, 2018		December 31, 2017		June 30, 2017		December 31, 2016
Consolidated Balance Sheets
Cash and cash equivalents	$	67,776	$	81,146	$	143,358	$	201,153
Restricted cash (included in other current assets)		2,388		2,383		2,378		—
Cash, cash equivalents and restricted cash in Consolidated Statements of Cash Flows	$	70,164	$	83,529	$	145,736	$	201,153