Subsequent events (Details) - 800 Boylston St - Subsequent Event	Jan. 27, 2017 USD ($) ft²
Subsequent Event [Line Items]
Area of Real Estate Property \| ft²	7,234
Operating leases, increase in future minimum payments due	$ 933,186
Security deposit	$ 126,595

The amount of an asset, typically cash, provided to a counterparty to provide certain assurance of performance by the entity pursuant to the terms of a written or oral agreement, such as a lease.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.8,17)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_SecurityDeposit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant