Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2018

Accounting Policies [Abstract]

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				Nine Months Ended
	September 30,				September 30,
	2018		2017		2018		2017
Operating Expenses
Research and development	$	95	$	1,419	$	1,855	$	4,400
General and administrative		1,218		2,160		4,434		6,701
Total	$	1,313	$	3,579	$	6,289	$	11,101

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
	September 30, 2018		December 31, 2017		September 30, 2017		December 31, 2016
Consolidated Balance Sheets
Cash and cash equivalents	$	62,605	$	81,146	$	118,783	$	201,153
Restricted cash (included in other current assets)		2,392		2,383		2,382		—
Cash, cash equivalents and restricted cash in Consolidated Statements of Cash Flows	$	64,997	$	83,529	$	121,165	$	201,153