Condensed Combined and Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Current assets
Cash and cash equivalents	$ 25,703	$ 51,615
Short-term available-for-sale investments	25,996
Prepaid expenses and other current assets	323	193
Total current assets	52,022	51,808
Property and equipment, net	14	8
Other assets	2,084	12
Total assets	54,120	51,828
Current liabilities:
Accounts payable	569	606
Accrued compensation	500	331
Income tax payable	63	155
Other accrued liabilities	1,280	432
Total current liabilities	2,412	1,524
Other long-term liabilities	165	230
Total liabilities	2,577	1,754
Commitments and contingencies (Note 5)
Convertible preferred stock	74,572	61,091
Stockholders’ deficit
Common stock—$0.0001 par value, 12,003,891 and 1,509,712 shares issued and outstanding as of December 31, 2013 and September 30, 2014, respectively		1
Additional paid-in capital	7,344	2,200
Notes receivable from stockholder		(335)
Accumulated other comprehensive loss	(11)
Accumulated deficit	(30,362)	(12,883)
Total stockholders’ deficit	(23,029)	(11,017)
Total liabilities, convertible preferred stock and stockholders’ deficit	54,120	51,828
Series A Convertible Preferred Stock
Current liabilities:
Convertible preferred stock	19,909	19,909
Series A-1 Convertible Preferred Stock
Current liabilities:
Convertible preferred stock	2,768	2,768
Series B Convertible Preferred Stock
Current liabilities:
Convertible preferred stock	$ 51,895	$ 38,414