CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities:
Net loss	$ (13,039)	$ (2,623)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	21	3
Stock-based compensation expense	1,222	43
Non-cash charges related to Vixen acquisition	2,784
Changes in operating assets and liabilities:
Prepaid expenses and other assets	71	(626)
Accounts payable	2,008	385
Accrued expenses	39	16
Net cash used in operating activities	(6,894)	(2,802)
Cash flows from investing activities:
Purchases of property and equipment	(40)	(77)
Proceeds from sales and maturities of marketable securities	10,214	822
Net cash provided by investing activities	10,174	745
Cash flows from financing activities:
Payment of deferred offering costs		(231)
Net cash used in financing activities		(231)
Net increase (decrease) in cash and cash equivalents	3,280	(2,288)
Cash and cash equivalents at beginning of period	9,851	10,757
Cash and cash equivalents at end of period	13,131	8,469
Supplemental disclosures of non-cash investing and financing activities:
Additions to property and equipment included in accounts payable	40
Accretion of convertible preferred stock to redemption value		$ 657
Fair value of stock issued in connection with Vixen acquisition on date of issuance	$ 2,355