Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
CURRENT ASSETS:
Cash and cash equivalents (Note 5)	$ 15,800	$ 29,154
Short-term investments (Note 4)	10,028	10,010
Prepaid expenses and other current assets (Note 5)	782	561
Total current assets	26,610	39,725
Property and equipment, net (Note 5)	397	214
Other assets (Note 5)	3,256	626
TOTAL ASSETS	30,263	40,565
CURRENT LIABILITIES:
Accrued liabilities (Note 5)	2,304	1,473
Accounts payable	1,925	622
Total current liabilities	4,229	2,095
Preferred stock warrant liabilities (Note 9)	10,641	1,810
Other liabilities	113	100
TOTAL LIABILITIES	$ 14,983	$ 4,005
Commitments and Contingencies (Note 6)
Preferred stock value	$ 297,652	$ 144,375
STOCKHOLDERS' DEFICIT:
Common stock, $0.001 par value; 180,000,000 shares authorized as of June 30, 2015 and December 31, 2014 and 1,616,514 and 1,588,701 shares issued and outstanding as of June 30, 2015 and December 31, 2014	2	2
Additional paid-in capital	0	0
Accumulated other comprehensive loss		(10)
Accumulated deficit	(282,374)	(107,807)
TOTAL STOCKHOLDERS' DEFICIT	(282,372)	(107,815)
TOTAL LIABILITIES, CONVERTIBLE AND REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' DEFICIT	30,263	40,565
Convertible Preferred Stock [Member]
CURRENT LIABILITIES:
Preferred stock value	2,543	2,543
Redeemable Convertible Preferred Stock [Member]
CURRENT LIABILITIES:
Preferred stock value	$ 295,109	$ 141,832