Condensed Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net (loss) income	$ (14,867)	$ 7,615
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Share-based compensation	1,698	1,411
Depreciation and amortization	27	29
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	986	(1,837)
Accounts payable	504	(697)
Accrued liabilities	445	(1,495)
Deferred revenues	(106)
Net cash (used in) provided by operating activities	(11,313)	5,026
Cash flows from investing activities:
Purchases of property and equipment		(2)
Purchases of short-term investments	(15,038)	(30,080)
Proceeds from maturity of short-term investments	25,043	25,057
Net cash provided by (used in) investing activities	10,005	(5,025)
Cash flows from financing activities:
Proceeds from exercise of stock options	189
Proceeds from issuance of common stock		4,212
Net cash provided by financing activities	189	4,212
Net (decrease) increase in cash and cash equivalents	(1,119)	4,213
Cash and cash equivalents at beginning of the period	8,458	10,837
Cash and cash equivalents at end of the period	$ 7,339	$ 15,050