Leases - Schedule of Cumulative Effects (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Assets
Other current assets	$ 34,842	$ 4,291	$ 4,103
Property and equipment, net	30,949	36,050	61,511
Operating lease right-of-use assets	37,573	42,010	0
Other assets	4,247	7,375	7,228
Liabilities
Operating lease liabilities, current	6,383	6,498	0
Accrued expenses and other current liabilities	43,138	8,271	10,908
Lease financing obligations, net of current portion	0	0	22,987
Operating lease liabilities, net of current portion	38,340	43,351	0
Other liabilities	2,306	5,639	9,290
Stockholders’ Equity
Accumulated deficit	$ (423,249)	(377,172)	$ (373,482)
Adjustments Due to Adoption of New Leasing Standard
Assets
Other current assets		188
Property and equipment, net		(25,461)
Operating lease right-of-use assets		42,010
Other assets		147
Liabilities
Operating lease liabilities, current		6,498
Accrued expenses and other current liabilities		(2,637)
Lease financing obligations, net of current portion		(22,987)
Operating lease liabilities, net of current portion		43,351
Other liabilities		(3,651)
Stockholders’ Equity
Accumulated deficit		$ (3,690)