Note 3 - Selected Balance Sheet Data (Details Textual) - USD ($)	Mar. 31, 2020	Jun. 30, 2019
Other Noncurrent Assets [Member]
Inventory, Finished Goods, Net of Reserves, Non-current	$ 3,649	$ 3,239,000

Non-current amount, net of valuation reserves and adjustments, as of the balance sheet date of merchandise or goods held by the company that are readily available for sale.

No definition available.

Name:	tech_InventoryFinishedGoodsNetOfReservesNonCurrent
Namespace Prefix:	tech_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant