Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 250,162	$ 72,080
Accounts receivable, net of allowance of $171 and $0 at September 30, 2015 and December 31, 2014, respectively	10,071	9,894
Inventories	9,460	4,809
Prepaid expenses and other current assets	6,120	2,865
Total current assets	275,813	89,648
Property and equipment, net	36,774	21,015
Restricted cash	1,395	864
Other assets	1,026	411
Total assets	315,008	111,938
Current liabilities:
Accounts payable	11,963	7,263
Accrued expenses and other current liabilities	16,069	7,414
Deferred revenue	455	340
Current portion of deferred rent	2,094	1,429
Total current liabilities	30,581	16,446
Deferred rent, net of current portion, and other non-current liabilities	10,953	9,323
Total liabilities	$ 41,534	$ 25,769
Commitments and contingencies (Note 13)
Stockholders' equity:
Preferred Stock, $0.0001 par value, 5,000,000 shares authorized; no shares issued and outstanding
Common stock, $0.0001 par value, 150,000,000 shares authorized; 34,396,872 and 28,223,958 shares issued and outstanding at September 30, 2015 and December 31, 2014, respectively	$ 3	$ 3
Additional paid-in capital	486,067	228,151
Accumulated deficit	(212,596)	(141,985)
Total stockholders' equity	273,474	86,169
Total liabilities and stockholders' equity	$ 315,008	$ 111,938