Income taxes - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Deferred tax assets:
Federal, state and foreign net operating losses	$ 55,540	$ 42,702
Federal and state tax credits	12,195	9,897
Stock-based compensation	3,481	5,044
Accrued expenses and reserves	18,475	11,664
Capitalized expense	60	174
Unrealized losses	609	717
Acquired intangible assets	652	822
Total deferred tax assets	91,012	71,020
Deferred tax liabilities:
Property and equipment	(29)	(329)
Capitalized software	(31,750)	(19,528)
Unrealized gains	(451)	(630)
Total deferred tax liabilities	(32,230)	(20,487)
Deferred tax assets, net of liabilities	58,782	50,533
Valuation allowance - worldwide	(58,254)	(50,083)
Net deferred tax assets	$ 528	$ 450