Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities:
Net loss	$ (3,198)	$ (1,684)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation of equipment	24	22
Amortization of intangible assets	166	166
Stock-based compensation	263	193
Net premium amortization on investments	5
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	15	(3)
Deferred offering costs		(146)
Accounts payable	517	34
Accrued expenses	(291)	(44)
Net cash used in operating activities	(2,499)	(1,462)
Cash flows from investing activities:
Purchase of equipment		(39)
Purchase of investments	(7,610)
Maturities of investments	5,800
Net cash used in investing activities	(1,810)	(39)
Cash flows from financing activities:
Proceeds from issuance of common stock from private offering, net of issuance costs	4,965
Proceeds from exercises of stock options	6
Net cash provided by financing activities	4,971
Net increase (decrease) in cash	662	(1,501)
Cash and cash equivalents at beginning of period	2,089	3,606
Cash and cash equivalents at end of period	$ 2,751	$ 2,105