Consolidated Statements of Cash Flows $ in Thousands, SFr in Millions	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Operating activities
Net loss	$ (23,202)	$ (25,828)	$ (6,800)
Reconciliation of net loss to net cash used in operating activities:
Depreciation and amortization expense	925	127	38
Equity-based compensation expense	10,844	3,684	695
Non-cash interest expense	8,050	97
Unrealized foreign currency remeasurement loss	2	(20)	(260)
Gain on extinguishment of convertible loan	(11,482)
Other income - formation of joint venture	(78,608)
Loss from equity method investment	36,380
Changes in:
Restricted cash	(2,450)	(650)	(16)
Accounts receivable	(2,818)	(339)
Prepaid expenses and other assets	(1,071)	(620)	(12)
Accounts payable and accrued expenses	3,860	7,708	1,583
Deferred revenue	1,917	75,090
Deferred rent	2,360	165
Other liabilities, net	(17)	14	(21)
Net cash (used in) provided by operating activities	(55,310)	59,428	(4,793)
Investing activities
Purchase of property and equipment	(3,016)	(1,154)
Proceeds from contribution of intellectual property to equity method investee	35,000
Cash investment in equity method investee	(100)
Net cash provided by (used in) investing activities	31,884	(1,154)
Financing activities
Proceeds from issuance of common shares in IPO, net of issuance costs	54,061
Proceeds from issuance of common shares in private placement	35,000
Proceeds from issuance of common shares			22
Proceeds from exercise of options	34
Proceeds from issuance of restricted shares		243
Issuance costs for preferred share financings	(1,810)	(370)	(36)
Proceeds from issuance of convertible loans	35,010	38,239
Net cash provided by financing activities	183,220	96,733	5,123
Effect of exchange rate changes on cash	(235)	9	254
Increase in cash	159,559	155,016	584
Cash, beginning of period	155,961	945	361
Cash, end of period	315,520	155,961	945
Supplemental disclosure of non-cash investing and financing activities
Property and equipment purchases in accounts payable and accrued expenses	7,014	246
Property and equipment related to lease incentives	10,785
Loss on extinguishment of redeemable convertible preferred shares			(745)
Conversion of preferred shares to common shares upon IPO	185,565
Conversion of Vertex and Bayer convertible loans and accrued interest	61,929
Issuance costs for public offering in accounts payable and accrued expenses	397
Contribution of intellectual property to Casebia	36,380
TRACR Hematology Limited [Member]
Supplemental disclosure of non-cash investing and financing activities
Noncontrolling interest upon consolidation of TRACR			547
Series A-2 Redeemable Convertible Preferred Shares [Member]
Financing activities
Proceeds from issuance of preferred shares		5,293	5,137
Series A-3 Redeemable Convertible Preferred Shares [Member]
Financing activities
Proceeds from issuance of preferred shares	22,850	22,850
Series B Redeemable Convertible Preferred Shares [Member]
Financing activities
Proceeds from issuance of preferred shares	$ 38,075	$ 30,478
Series A-1 Redeemable Convertible Preferred Shares [Member]
Supplemental disclosure of non-cash investing and financing activities
Loss on extinguishment of redeemable convertible preferred shares			$ 745