Income taxes - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Jun. 30, 2016
Deferred tax assets:
Federal, state and foreign net operating losses	$ 42,702	$ 16,482
Federal and state tax credits	9,897	6,696
Stock-based compensation	5,044	4,747
Accrued expenses and reserves	11,664	5,465
Capitalized expense	174	252
Unrealized losses on investments	717	727
Acquired intangible assets	822	596
Total deferred tax assets:	71,020	34,965
Deferred tax liabilities:
Property and equipment	(329)	(468)
Capitalized software	(19,528)	(3,734)
Unrealized gains on investments	(630)	(353)
Total deferred tax liabilities:	(20,487)	(4,555)
Deferred tax assets, net of liabilities:	50,533	30,410
Valuation allowance - worldwide	(50,083)	(29,820)
Net deferred tax assets:	$ 450	$ 590